I don”t know if it was there before but i have a strange problem.
EX: -Having 2 layers both on add blend
Botom layer full clip
Top layer clip with slice transfor or alpha
If botom layer is between 0-50, value .. when you “go up” with top layer it messes the oppacityof the botom - until you reach 50 value.
the problem is eaven worse when you work on 50 add, because the opacity of your bottom clip is working after 25%.
LE: the problem is on any blend like lighten, multyply, diference darken etc.