Boat: 2014 Skeeter TZX 190 Motor: 2014 175 Yamaha HPDI

Hoping for some insight here... A few weeks ago while running WOT my boat just died. Come to find out that my tank wasn't venting and it collapsed the primer bulb restricting fuel to my motor. Shop told me that it was most likely the filler neck that was causing the problem (See attached), BUT the shop tested it on an electric fuel pump they said the tank was venting just fine. I did go in and remove the carbon canister and bypassed it with a steel nipple and that seems to have worked fine, however this past sunday when i got home i opened my gas gap and watched my tank at the same time and it took in a big gulp of air and i saw my tank expand back out. Has anyone ever had this issue? Is it normal for the tank to create some vacuum? My motor has not shut off again since that one occurrence, but i am worried if the tank is not venting correctly that it could eventually damage the electric fuel pump. I also noticed when filing my tank and i can smell fumes coming out of the vent port but do not really smell fumes when it is running/sitting coming out of vent port.IMG_3656.jpg