Seems like Pagefile needs to be set to C:\ with 2402 and later, even if there's a Cache Disk. Session Manager "This session will be disconnected due to a policy evaluation error" - Page 2 - XenDesktop 7.x - Citrix Community

Good morning, we also encountered the problem by updating to PVS TargetDevice 2503. The pagefile was swapped to the WriteCache disk via BIS-F when the image was created. This has been adjusted accordingly. Now the PVS software automatically forwards the page file to the WriteCache disk: PVS target software redirects the system page file to the same disk as the write cache file, so pagefile.sys allocates space on the cache drive unless manually setup to be redirected on a separate drive volume. Source: Tech Brief: Citrix Provisioning - Tech Briefs

Fix should be included in 2503.1

Ah perfect, thanks for the info @Balint Oberrauch