You are right. I just tested this with my work iPhone. If I select my work Exchange account’s calendar and start typing in the location field the location icon appears in the status bar and locations are suggested. However if I select my Sogo account’s calendar (also added via Exchange to my iPhone) the location icon disappears and therefore nothing near my location is suggested.
But I don’t think this has to do something with Sogo… I’m using Android on my private phone and with the Google calendar app it works. Maybe someone with Apple experience can bring some light into this
Ah okay, it’s indeed due to Sogo…
It seems that iOS enables this feature only when the server provides EAS protocol version 16.x
https://bugs.sogo.nu/view.php?id=5340&nbn=4
Workaround is:
Connect via CalDAV/IMAP on iOS with SoGO, then location with maps works properly.