amp works with 1 sub and not 2

So here's my setup:

Audiobahn a8002T

200.0 Watt - 4.0 Ohm - 2.0 channel(s)
400.0 Watt - 2.0 Ohm - 2.0 channel(s)
800.0 Watt - 4.0 Ohm - 1.0 channel(s)

2 10" JL 10w-1

4 ohm single voice coil
125watt RMS

Ported box

Now that all of that is out of the way. Here's way happens.

hook each sub to each channel and the power light will continually fade out (along with sound) After a few times of this it'll eventually cut off and then turn back on and the sub will shoot out and then th protection light will come on.

hook 1 or 2 bridged............ same thing..

hook 1 to 1 channel and it works perfectly.

Any suggestions?

TIA

you may want to check your ground onto the amp. this may be a problem as well as the subs may be internally shorting out. check for clipping as well