Windows agent plugin output not transferred to checkmk server

CMK version:
2.3.0p30
OS version:
Ubuntu LTS 22.04

I wrote a small agent plugin to check Windows iSCSI target connections a while ago. With 2.3 this stopped working.
I discovered, that the agent plugin now is (per default) only executed in \programdata.…\plugins, not in programfiles(x86)…
I copied the plugin to this location (its a 2 line PS script, see code at end) and if i execute

.\check_mk_agent.exe test

it gets executed and i see the output as expected.

If i run

cmk -d SERVER 

on checkmk server, the section of this plugin is not in the output.

What do i miss?

PS plugin script:

write-host '<<<iSCSI>>>'
(Get-IscsiTarget | format-table NodeAddress, IsConnected -HideTableHeaders -AutoSize | Out-String).trim()

Output of script:

<<<iSCSI>>>
storage-iqn:hv1         False
storage-iqn:user        True
storage-iqn:wsus        True

Do not know why, but after restartign checkmk agent service, it is working now.