Switching to stabel... iris+ drops like a brick

Hi,

i received my IRIS+ a week ago and it flyes awesome. Last time i mounted the tarot gimble and gopro. i went out and put my IRIS into the sky. first takeoff in Stable mode… a lot more weight (you can almost feel it in your transmitter sticks). but with gimbal it flyes great. After take off in stable mode i put the IRIS+ after a few minutes into Loiter mode… again flyes good. Then fly for a couple off minutes in Loiter mode to return to Stable mode. But when i had put it in stable mode, the IRIS+ came down like a brick and i had to give almost full trotthle to gain alltitude again and to prevent it from hitting the ground like a drill. Lucky for me and my IRIS+ i had enough alltitude when this happend.

whats wrong here, i tryed to figure it out in the log files, but i have not enough experience yet to read the logs the proper way. I have the log file attached.

Can someone clear and help me out here please?

thanks

@vindouw,
You did not attach either a tlog or a data flash log.
Regards,
TCIII GM

sorry,
i did not notice the warning about 5mb max upload. i have now zipped the log file… (its 19 mb)…
and now attached…

thanks