Joplin may delete local item by mistake

After a conflict happend and fixed, local items/pictures will be deleted when I'm synchronise the notes.

Then the pictures will be seen like this:


I can see the message behind:
The following attachments are being watched for changes:

The attachments will no longer be watched when you switch to a different note.

I'm using Jopin on macOS High Sierra 10.13.2 and Ubuntu 16.04.

Could you please tell me how to deal with the situation? Thank you!