That makes sense to me.
Interestingly the recorded file has a frame rate of 57 Hz.
Could it be that on iPhone 15 Pro the ProMotion is not honoured by the App? On iPad it works smoothly most of the time. But on iPhone it is instantly slow.
As soon as I get some free cycles I’ll see what I can figure out with this. Unfortunately, I just found out that the pro motion stuff isn’t available on iPhone 12 which is the iPhone I have 
So, I’ll have to see what I can figure out.
Roon should pay you enough to be able to buy a phone less than 6 years old 
I’ve had something like 5 phones since that iPhone. However, it is the only iPhone I’ve ever owned 
Ok today it started getting slow. So I closed the app (not force quit, I know that fixes it) and started the recording. Then I opened Roon and it was smooth - and stayed like that after recording ended. Not sure if the few seconds in the background or the recording fixed it.
Ok, @connor I have a recording for you
I was scrolling through my library, listening and organising when I found it more and more laggy. After a restart it was smooth again. In this video you see a part of the screen when it was lagging and when swiped to the right it is the situation after the restart (smooth). Hope this makes sense.
How can I send it to you?
@connor Once you get the recording, can you share it with me?
Sorry everyone. This Apple “27” release has stolen all of my time lately
I sent a pm to both of you.
Thanks for your help.