System fans including GPU fans spin when system is completely off

So I've recently transferred a system to a new case and wired everything up put the side panels on and put power to it and nothing which most likely means I messed up the power button some how so I took off the side panel laid the system on it side made sure everything was ok and then put power to it leaving the side panel off now this is where it gets weird. Without hitting the power button all the fans in the system turn on and stop and turn on and stop. When I remove power they stop I figured well maybe the power button is stuck and causing the system to turn on and off repeatedly so I removed the power button connector and it still does it. I've never had this happen before and was hoping someone could tell me why.

Dehumidifier function or something along those lines?

Yea but its been disabled in the bios. I unplugged all the power connectors (CPU, motherboard) and reseated them and it worked fine so I'm guessing it worked itself out

So the system stopped acting weird?

Yea it stopped I guess something wasnt seated properly?

I don't know. I've had something similar happen to me too but the system was booting fine. After a couple of reboots everything went back as it used to be. Even once or twice the system double booted (boot, turned off and than on again) on it's own but nothing looked like compromised. Tech likes to act weird. Monitor the situation and if nothing happens anymore just forget what happened.

This system has been weird from day one. It use to turn itself on after I had shut it down or would just turn on in the middle of the day and some days it would out right refuse to shutdown. Click shutdown would go through the closing of all the programs and then just sit there or you'd click it and it would act like it was going to do something then nothing would happen reinstalled the OS and it fixed that problem but hopefully this issue has worked itself out.