Correction and Resolved
A slight correction: the cubic housing out of which the circular In port juts is slightly loose, whereas the Out housing is solid.
I fixed the problem by jamming a little bit of paper into the gap between the top of the metal casing and the square-faced black plastic housing to keep the port in place. It's not a perfect solution but the connector is performing much more reliably now. I presume glue would be of help as well.