So the problem (as I pretty much expected it to be) is the user here. But I put this partly on OP too, due to their lack of documentation (or perhaps my lack of finding said documentation) of OOS.
Seems I've been using the sweeper to close recent apps instead of the 3 bars on the far right. The sweeper kills the app process, background services and even resets accessibility settings. Not exactly what I had in mind when I only meant to close recent apps. I learned this tidbit of info over on the OP forums at Oneplus.
So now that I'm using the 3 bars to close recent apps, all seems to be running normally and as I would expect.
So where is this documentation that I must have overlooked about the extras that OOS adds to 6.0.1? :-[
That's not a OOS issue is it?
By using sweeper surely you are killing the app?
The clear all recent apps is a OOS feature as isn't in stock, however this just stops the RAM usage, background data will still process, sweeper kills the background data.