I received an error message from Chrome yesterday about a restriction in Incognito mode. I do agree that sounds like the conflict.
It's apparently a feature not a bug.... Chrome for Android, version 65, a "feature" release. This was released to hide incognito from recent apps, thus making incognito more hidden... however they have this all merged under one section of code
Here's the code:
--enable-incognito-snapshots-in-android-recents
Unfortunately the session/settings doesn't have a chrome://flags option to make screenshot locks optional(screenshots should never be locked out IMHO), but do understand the corporate/ government worlds wanting to restrict that feature with some apps.
At the moment there is a campaign in the developer community requesting this "optional" flag feature.
add the flag to chrome://flags however the developers current status is "Won't Fix"
https://bugs.chromium.org/p/chromium/issues/detail?id=920762