I'll be replying here for the meanwhile as it's in a public forum.
Did you misplace the large oring on the can/powertube?
We have had issues with leaking markers due to eye cover screws protruding excessively into the breech which destroys the oring gland as pictured here:
In the above case, the stock bolt also saw signs of damage.
Overall, we have had no issues with the E1 when we tested it ourselves, our testers have not found any problems, and all negative feedback from customers has been discussed and found to be either an oring missing, orings not lubed, general user error, or damage caused by these eye cover screws which do not necessarily stick into the breech on all markers.