Syncing issue with contacts across Apple devices

I have an iPhone, an iPad, and a newly acquired MacBook Air.

I have gmail, and use the gmail app on iPhone/iPad and the Apple mail app on MacBook.

All my contacts are stored in Google Contacts and nowhere else.

There is a strange syncing issue. If I add/alter a contact via any of my Apple devices everything syncs everywhere else.

However if I delete a contact via iPhone/iPad, it doesn't show as deleted on MacBook, whilst if I delete via MacBook it doesn’t show as deleted on iPhone/iPad. Furthermore if I delete a contact directly on the Google Contacts page, it does show as deleted on iPhone/iPad/Macbook.

I have spent many hours trying to understand what is going on here but with no success. I have double-checked all my settings and have turned things off and then back on again.

Am I missing something obvious or could it be a bug in the system?

Any advice would be much appreciated.