Airmail 3 for Mac v. 3.3.2

when opening a conversation, there's the actions on the top that should apply for the entire conversation.
When selecting a single message from the conversation, there's the same actions - just that they should only apply to that particular message.

However, that distinction does not work.

I've single-moved the oldest message in a conversation to a folder - yet the whole conversation moves along.

I've single-deleted the most recent message in a conversation - yet the whole conversation goes to the trash can.

mailed this bug report to tech support, but no reply after a month ...
that's a pity: I really like the tool, but still have to revert to Thunderbird from time to time to solve Airmail issues like the above.