PROBLEM REBOOT WYSE 3040 (2020) AND 8.6_511 OR UNDER

Hello,

I have a problem with some Wyse 3040 year 2020, following the migration to firmware 511, the reboot no longer works, I have to turn off the thin client to restart it.

However, other Wyse from the same year are working perfectly after the migration (same group, same settings).

If I downgrade to version 017, the reboot works ??? Any explanations or solutions to offer me?

Thank you very much