Yealink Cordless Base Dropping Server Details

In the last couple of days, we have had 3 customers who have a Yealink W60 base with 1 or more handsets who have reported their phone showing “no service” and the registration is not showing in the PBX.
When we organise a remote session and log in to the base, all details are still in the auto prov section, and all the correct details in the Accounts section, all except the server. UN, PW, UDP etc all still in place. We just add the server and it immediately reregistered.
We have a heap of customers on another PBX and no one still on that PBX reported such an issue, so it is definitely Vital specific.
1 customer I wouldnt bother reporting it, but 3 customers, there must be something triggering this all at the same time.

If Vital PBX is pushing out provisioning updates (via auto-provision URLs or template manual syncs), it can overwrite or clear specific fields. This smells like a template issue.