[Oz Cello]

I had a similar problem. I hadn't used the companion for quite a while and just started again the other day with the upgraded version. My devices are Boox Max 2 running the e-Ink app. Which each new import I did into the companion, when I clicked save it would save it but rather than closing the dialogue for the piece it would open a new dialogue asking whether I wanted to save the changes or discard them. I found that if I chose to save the changes it would then save the same piece a second time (i.e. as a separate entry in the library). If I choose discard changes then it does what I want which is to close the dialogue with just one piece saved.