timo
Thanks for getting back with me.
Yes, I've left the app to run for over an hour while I do other stuff on my computer, and when I go back it still has not synced and the only way to quit is to force quit.
Good question about the new data. I added new data via the app on my iPhone today and when I opened the app on my Mac it synced almost instantaneously.
As far as I am aware my internet connection is working normally. When the issue happens I'm able to do other internet related tasks. When I do experience issues I have not checked whether iCloud is accessible from within other apps; I'll do that the next time I experience the issue.
The arrows start off rotating, go for a period of time (5 min?), then stop. They are greyed out as well. Next time this happens I will capture video and share that with you.
Appreciate the help!