Problems with unless in a PromQL Query in a Dashboard

Hello,

i have some Issues to bring a Panel to work with a query containing the unless function in promql.

here is the Example that i want to implement

Values Query1 : ----- Values Query 2:
A --------------------------A
B -------------------------
C ------------------------ C
D ------------------------ D
E ------------------------ E

This should give me the Value B as Result. This is working in the Grafana explore panel. But this is not working in the panel for visualisation. Do you know if there are limitations or bugs in the Grafana Dashboards.

The Grafana Version is: Grafana v10.1.5 (849c612fcb)