I'd suggest that you either check that expansion chamber yourself or have it looked at. All the chambers I've seen so are have the input at the base and the output at the top which forces the liquid and gas to flow up through all the stages. For the one you have to work right there would need to be a hole from that inlet down inside the wall to the base. That seems unlikely to me so I'm wondering if someone in the past drilled and tapped the chamber that way in ignorance nor realizing that it would bypass all or most of the chambers.
The zip tie isn't for the trigger frame. The frame ends before where the zip tie is located. I notice that the chamber is sort of suspended by a screw or screwhead. Perhaps it's holding on the chamber somehow.
And just as a thought that bottle will be right where you want to put your cheek when sighting along the barrel. Not to mention that the line setup looks very awkward for getting your hand into and out from in a hurry. You may want to look into a bottom line setup to cure that unless you're planning on mounting some form of tall bridge style sight rail.
I had a "Paintball God" moment once.
Like Al Bundy's Polk High football moment I live on
for the slim chance of repeating that one time
miracle in some small way.........