O/C alarm from the PA100-D when switching bands

[va2dv]

Hello group,
I using the PA100D with an Icom IC-705. The 705 is set at 5w.
The amplifier is in automatic band switching mode.
When I change the operating band on the radio, let's say 40m to 20m, the amplifier does detect the frequency change but I got a O/C alarm and must recycle the amp with the power button. It's a bit annoying since I am using this setup remote.
I know it is probably a very simple thing but cannot find the root cause.