I have a 2017 MacBook Pro. I was running High Sierra but I downgraded back to 10.12.5 then updated to 10.12.6 due to Logic Pro not working in Beta 3. During my downgrade period, I installed Boot Camp and have Windows 10 Education partitioned. Now when Beta 4 came out, I wasn't exactly sure to install but I heard good things so I did. I didn't see it ask me to convert to APFS like the last betas, so I expected it to stay HFS+. But it converted to APFS anyways. So now it has the volume container of APFS and then a partition of Windows which can't be removed since APFS volumes can't be resized. Another issue is that when you start up the Mac and hold down the OPTION key, Windows shows as the first disk. And without changing the start up disk, if I booted into Windows last, it will keep booting into Windows until I restart the computer and hold option again, since Windows doesn't even read APFS. Here's what Boot Camp Assistant says.
How is this going to work in the future? Will future betas fix this? Also, has anyone else had this experience? I just want to know how people live with it.