Scrolling Lag on 13" MacBook Pro w/Touch Bar and High Sierra

cambookpro

macrumors 603
Original poster
Feb 3, 2010
6,402
1,841
United Kingdom
Hi,

Have an odd issue I'm wondering if anyone else can replicate.

I have a 13" late 2016 MacBook Pro. After a period of inactivity, the Touch Bar and keyboard backlight will dim to save power. After this has happened, if you attempt to scroll on the trackpad or mouse as the first interaction after it has dimmed, there is a noticeable problem which results in the page jerking to the point where you would have scrolled to without an animation. The app will do the 'jump' once the Touch Bar has returned to full brightness, and then scroll normally.

Happens in Safari, Messages, Finder, Preview, and I presume all other apps.

The only other mention of this online I can find is one Reddit thread, which suggests it may affect 13" MBPs, with one poster suggesting it only affects i5 CPUs. I have a 2.9GHz i5, but can't find any source for this claim.

I can't remember this happening in Sierra, so might be a High Sierra bug?

Would appreciate if anyone else could share their experience, and whether this is a widespread issue, or something caused by the software on my laptop. I tried to boot into Safe Mode, but when the loading bar on the startup screen fills, it seems to hang there. Left it 10 minutes and it still hadn't booted and not sure why.

Thanks
 

cambookpro

macrumors 603
Original poster
Feb 3, 2010
6,402
1,841
United Kingdom
Just in case anyone has the same issue, have submitted the bug to Apple and it's been marked as a duplicate - so hopefully they're at least aware of it.

As a temporary workaround, I've set my keyboard backlight to only dim after 1 minute.
 
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abn5x

macrumors member
Jul 21, 2018
46
42
same case here, today they asked me if it still happens in latest Mojave, and sadly yes... it still happens
 

ralliart12

macrumors newbie
Jun 29, 2010
5
1
Thanks for posting, that's very disappointing that it isn't fixed. It's a small thing but very noticeable when using the laptop.
This happens on my 2017 15" (2.9/512/560) as well, and is quite annoying. Exact same symptoms.
But I have to say, the issue comes and go, because right before I brought my MBP to the first Apple visit, the problem went away, so I couldn’t replicate the problem to the Genius. They asked if they can reformat my MBP anyway & since I’d nothing to lose I went ahead. & of course the problem wasn’t there after I reformat. So I’d no further business at the Genius bar. Went home & the problem came back within a few reboots (& before I even install any 3rd-party software). But the creepy thing is, the problem comes & goes. I’d another upcoming appointment but Apple says they are likely to go the hardware diagnostics part (aka tear my MBP apart), which I’m extremely unwilling to.

For those of you with this issue, is the issue reliably replicating, or it comes & goes?

I tried on 3 different MacBook SKU at the Apple store and couldn’t replicate the issue (lucky for them) with the exact keyboard light timeout setting as mine, but I wonder if I’d simply caught them 3 MacBooks on “a good day”...
 

cambookpro

macrumors 603
Original poster
Feb 3, 2010
6,402
1,841
United Kingdom
But I have to say, the issue comes and go, because right before I brought my MBP to the first Apple visit, the problem went away, so I couldn’t replicate the problem to the Genius. They asked if they can reformat my MBP anyway & since I’d nothing to lose I went ahead. & of course the problem wasn’t there after I reformat. So I’d no further business at the Genius bar. Went home & the problem came back within a few reboots (& before I even install any 3rd-party software). But the creepy thing is, the problem comes & goes. I’d another upcoming appointment but Apple says they are likely to go the hardware diagnostics part (aka tear my MBP apart), which I’m extremely unwilling to.

For those of you with this issue, is the issue reliably replicating, or it comes & goes?

I tried on 3 different MacBook SKU at the Apple store and couldn’t replicate the issue (lucky for them) with the exact keyboard light timeout setting as mine, but I wonder if I’d simply caught them 3 MacBooks on “a good day”...
Hmm, I had thought it was re-producable 100% of the time, but I've just tried it now and it was fine. I am running Catalina though, so not sure if it's just a case of this bug being fixed in 10.15 or if it was truly intermittent. I have my keyboard backlight to turn off after 5 seconds and will test over the next few days to see if it happens again.

For what it's worth, I couldn't reproduce it on a 2017 or 2018 13" MBP both running Mojave.

Edit: Never mind, as soon as I posted this, I scrolled up the thread and it occurred... seemingly it doesn't happen straight away after the keyboard light times out if set to 5 seconds, but does if set to 30 seconds. I have no idea what's going on here.
 

CheesePuff

macrumors 6502a
Sep 3, 2008
571
313
Southwest Florida, USA
But I have to say, the issue comes and go, because right before I brought my MBP to the first Apple visit, the problem went away, so I couldn’t replicate the problem to the Genius. They asked if they can reformat my MBP anyway & since I’d nothing to lose I went ahead. & of course the problem wasn’t there after I reformat. So I’d no further business at the Genius bar. Went home & the problem came back within a few reboots (& before I even install any 3rd-party software). But the creepy thing is, the problem comes & goes. I’d another upcoming appointment but Apple says they are likely to go the hardware diagnostics part (aka tear my MBP apart), which I’m extremely unwilling to.

For those of you with this issue, is the issue reliably replicating, or it comes & goes?

I tried on 3 different MacBook SKU at the Apple store and couldn’t replicate the issue (lucky for them) with the exact keyboard light timeout setting as mine, but I wonder if I’d simply caught them 3 MacBooks on “a good day”...
I'm also able to reproduce every time on my 2017 15", as soon as the keyboard backlight and Touch Bar go off, there is the slight lag when scrolling on the track pad.
 

Orackle

macrumors newbie
Sep 17, 2019
1
0
Same exact issue on my new 2019 13inch Pro. After toying around with the issue for a couple of days I noticed that it only occurs when TouchBar is set to show "app controls" AND keyboard backlight level is above zero.

Even if touchBar is set to show control strip by default and only show "app controls" when you press "FN" button. Lag is there if you press "FN" button and wait for backlight timeout.

If touchpad shows anything but "App Controls" - lag never appears.

If you scroll in the inactive window - lag never appears.

It does not lag in the safe mode as far as I can tell, but scrolling in safe mode is already laggy enough.

And the most infuriating part is this bug comes and goes, sometimes it's there and sometimes not. Resetting NVRAM and SMC does not fix it. Reinstalling system does not fix it. It appears even in the guest account. Honestly I am at a loss, as I tried everything. The only workaround now is to turn off backlight timeout or switch Touch Bar to show Control strip or F-keys. If anyone stumbles upon this thread and has a solution, please reply