I had a look at the engine log file and found this error message:
2021-03-11 09:09:31 Failed to monitor folder /Users/hl/Dropbox/CT/Test
I have searched All macros for '/Users/hl/Dropbox/CT/Test' and 'monitor' but I cannot discover which macro causes this error message?
You may not have the full path in the macro itself; it could be a Tilde ($HOME) based path.
There is no “monitor” function in Keyboard Maestro to find – but there is a Folder-Trigger.
I just searched my own log for "failed to monitor" and found some entries, such as:
2020-11-26 05:52:38 Failed to monitor folder /Users/chris/Dropbox/Clients
Searching the Keyboard Maestro Editor for:
Gets the job done.