Despite setting the HDX policy to use client time zone, the time was still different on the client than the endpoint.
Checking the usual places in the registry and some W32TM queries revealed nothing…
w32tm /query /source w32tm /tz
Then I manually tried to change the time zone on the XD machine…error – can’t! Time to check permissions. Looks like users need to have the ‘Change the time zone’ right for this to work, and in this example, they did not. SecPol > Local Policies > User Rights Assignment > Change the time zone