Q: iCloud Calendar defaults to 'New Event'

Dear All,

I'm experiencing a small but significant issue with my Mac Calendar.

When I make a new entry - let's say 'Meet John Smith' - after a few seconds the entry changes to New Event.  When I re-type the original entry, Calendar retains my text.  I guess this is something to do with iCloud sync, but I don't know.  I also wonder if it might be because my iOS is a newer version than my Mac OS.  Again, these are just guesses.

The issue doesn't seem to occur when I set an entry on my iPhone.

My devices (and software versions) are detailed below.

Any suggestions would be most welcome.

Thanks in advance,

Roger