Hello Charraya and welcome to the ArtRage forums 
For your first question;
Looking at your screenshot, (love it when people include screenshots with questions!) Layer 34 and the two below that do not appear to actually be in the Head Group.
When Layers are inside a Group they will have one or more small folder icons just to the left of the layer’s thumbnail.
If a layer is in a group that is within another Group it will have two folder icons next to it denoting how far down it is nested and so on as more Groups get nested within Groups.
When dragging Layers or Groups into other Groups try and make sure you are dragging them into the centre of the Group’s Header. You will see a small arrow at the right of the Layer stack indicating just where a Layer or Group will be dropped.
By way of a demonstration, you can see here that inside Group ALL I have two other Groups. The layers in these two “sub-groups” will have two folder icons on the layers inside them. But the bottom Background Layer only has one folder icon as the only Group it is in is the first Group ALL.

As to your second question that’s trickier to answer as I can’t replicate that behaviour here I’m afraid.
Can you give any further details?
Which OS are you on?
Dose it always happen in every painting or just one in particular?
Dose it happen after a set number of undo steps? Etc…
Last edited by markw; 07-23-2020 at 11:31 PM.
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