Need Help, Fuel draining back

[alexx1060]

hey guys, 3 days in and I'm running out of options.
2011 KW T660
CM871 with electric low-pressure pump

Current symptoms:

Turn key to Ignition ON position, fuel drains into tanks from both Clear Housing filter (many air bubbles clearly visible) and from the on Engine filter. Seems to be free flowing as if someone is just pouring it out.

Tried Bypassing the Chassis filter, same result.

Can hear the low-pressure pump motor running for sure.

Any advice would be appreciated!