Passcode requirement change? Malware?

Hi everyone, thanks in advance.
This morning when I turned on my phone, I had a strange popup message that said "you must change your passcode within 60 minutes." I bit and changed my (4 digit) code in the box, but I became concerned it might be malware and also changed my code manually. The only reason I currently have to think it could be malware is because it was an odd message. As of this writing, it hasn't happened again. I couldn't find much on Google.
Some details:
I am running a 6+ with iOS 8.1. I have not downloaded any 3rd party apps or clicked any links (I honestly only have "popular" apps on my phone since I recently received it). My phone is in no way linked to any work profiles. I do have a gmail account synced to the phone. I'm not jailbroken.
I think that is all the relavant info- thanks.

 

No. This is a completely personal use phone, and I've only had it for about 2 weeks. My (one) gmail account is all I have synced.

A cursory Google search suggested that it could be a software bug? Or possibly "too simple passcode" but I've always used a 4 digit password (and used this passcode for 2 weeks) so I'm not sure why an alert would be triggered now. I have downloaded anything on my phone for about 1 week.

 

Yeah good points, although profile was the first thing I checked. There's no profile section for me under settings-general, and I've never had any phone associated with a management profile.

When I set up the phone, I set it up as a "new iPhone", not a backup.

Very weird, if it happens again I will screenshot it. I have a new passcode so hopefully that solves my problems...