Oh I can do that, first thing I tried. Not even sure the purpose of that layer mask.
Trying to reproduce the 'bug' with a simplified version, a couple of layers in a layer group, that disabled layer mask, a bit of text on top of everything. Not buggy so far.
Edit: Ah, layer group is in pass-through mode. Changing to normal seems to fix it. ...nope... still not able to replicate it in a simplified form.
Edit: I wonder if the whole thing originally came from a PS file ?
Trying to reproduce the 'bug' with a simplified version, a couple of layers in a layer group, that disabled layer mask, a bit of text on top of everything. Not buggy so far.
Edit: Ah, layer group is in pass-through mode. Changing to normal seems to fix it. ...nope... still not able to replicate it in a simplified form.
Edit: I wonder if the whole thing originally came from a PS file ?