This is from clicking the image preview directly in compact mode right? I seem to have the save and share options in compact mode, but not sure why different from you.
Edit, sorry, ignore. I had not updated to the latest version yet. I also have the same bug now.
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.