Auto Fill Email addresses in Apple Mail

I use Apple Mail on numerous Macs (all running MacOS 14 Sonoma).... home, office, laptop accessing the Office (MS Exchange mail) and my iCloud account. I have my iCloud address book active but do not regularly update it, I do not use my Exchange address book, rather I rely on previous recipients or "found in Siri" to provide email addresses from people that I communicate with regularly (almost exclusively using my company email).

I am finding that the auto fill when addressing an email is pulling up old addresses from my iCloud address book (expected) but not showing addresses that I have recently used, many times, from any of my machines.

Are there some limitations that I am hitting? Corruption in previous recipients? It is very frustrating as I am the only person in the office that has this issue and all function in a similar manner as I do.

Any suggestions would be much appreciated.