OS: 11.3.1

Playing game, swapping between dungeons and campaign while leveling heroes (Hard, brutal and nightmare campaign.) Noticed i was missing some 3 stars on nightmare Dreadlands, i got unsure if I had cleared them as i wasnt going systematicly, but jumping back and forth to Level up Steelscull. Many og the stages I have cleared manually, and retrospective I am positive that I have cleared them several times without getting my 3 stars. I have spent loads of time and gems to load Energy for this as the second hero isnt lvl 60 yet and made me fail several times.

Missing my stars at Nightmare stage 9.1, 9.5 and 9.7

Screenshot from 9.7 should be enough to prove as both heroes are standing alive in background. i only Get 2 stars.