Thanks for replying.
I'm in Partial mode with tracking and replay tag set to off, and the others to channel, and the previous OS was version 10.4, so quite a large jump.
I was looking through the changelog, and I think the problem is with 8.5 Replaying memories(Tracking)
This might be what's happening, but not sure.
Also, could you clarify on what it means by memory stack/playback stack? Do memories inherit features of the memory before it (say mem1 has colour yellow and mem2 has an edited position, mem2 would be the position but with yellow colour?)
I'll do some testing tomorrow and update back. I'll also try to include images and gifs.