Job fails to run on PS5.1 after upgrade from 2026.2.4 to 2026.3.4

Regardless of script - I've tried multiple and a simple ```Write-Output "hello world"``` type script, I just get failed jobs when attempting to run in a 5.1 environment after upgrading to 2026.3.4.

PSCore scripts all seem to work fine.

I've removed the existing 5.1 environment and auto re-discovered it, updated my script's environment to this, and retried but it's the same. Also tried rebooting the server to no effect. When switching the same script to use a PS Core environment, it works fine.

Is this a known issue with the latest update?

Environment details:

Installed as a service, running under a service account on windows.

Server sits behind squid proxy with limited outbound access.