BUG: IDEX temperature goes down when dual print [KLIPPER 0.11.]

Hello,

since my update today to klipper 0.11.0.5 my idex printer can’t print with both heads. When I print with each head alone it works with each one, bute with both together not. I’ll print a two colored cube where both hotends must work. The print start and while the brim is printed I see on the display that the temperature goes rapidly down, but only at the active head/hotend. Before with klipper 0.10. it works fine.
Any ideas what it can be?
klippy.log (3.7 MB)
moonraker.log (72.7 KB)

SOLVED: I don’t unterstand why it works in single mode!? But I found the problem it was a broken cable.