Leaky transition?

(version of August 4, 2024) I share this schematic model of one of the quick coupling devices provided as a background for the challenge, with imprecise dimensions obtained from a photograph. I used it to analyze a "long transition zone" during coupling, in which the pressurized fuel does not seem to be properly sealed. I leave you the individual images with which I made the animations because they are much better to see "step by step" what happens. SolidWORKS 2020 and STEP