Character distorts in Animate CC every time I select all frames

I have been using Animate CC since 2020 and recently I ran into an issue I can't get my head around. I have drawn a character from scratch in Animate CC and put every part on a different layer, converting it into symbols afterwards and then joined every layer using the layer-parenting.
But the character distorts and the ctrl+z button also goes ineffective when I use the up and down button after selecting every frame, I mean from frame 1 to the last frame.

I don't know what to do. the problem seems layer-parenting specific.

I have tried doing the same in other versions of animate cc, but the same problem occurred there as well.

help me find a solution. I am attaching the images!