If you go into the comments and collapse the second level reply to a first level reply to the post, and then try to collapse the first level as well, the app doesn’t behave correctly and instead expands to show the replies in the third level.
Apologies if this is worded poorly!
Here is an image example (not viewable on Memmy). The Yellow color coded comment is the third level. The second level in between has completely disappeared. This is after collapsing the second level and then collapsing the first level.