We do testing continuously, you are right that isn't your responsibility as a customer. However, when you encounter a problem we haven't seen, we ask for how to reproduce the problem so we can fix it. If you can't provide that, that's OK, but unfortunately it may take longer before we can encounter the problem ourselves so it can be fixed.
Software is complex and there will always be bugs to be found. If someone says otherwise, it just means they aren't looking hard enough. I'm sorry you are encountering bugs, but know we are dedicated to finding and fixing them.
It isn't clear exactly what you see as being incorrect in the tree. Is the attachment visibility correct in the viewport but the visibility dots in the tree are incorrect?
I see you have filtered your tree view. Can you show what filters you are using? Does removing the filters to show everything affect the bug you see?