Argee, where did you get the Wilson front grip strap for your ultra? I can only find them for full-size 1911.
It very well may have been strictly a feeding issue. Whatever it was, it was inhibiting the expulsion of the spent cartridge. Someone suggested tweaking the magazine which corrected the problem. By all means I will conduct that test to eliminate any underlying problems that may exist.You solved the feeding problem
I have no idea how bending the magazine would solve the ejection problem.
I suggest you run the extractor function test I posted to be sure that problem is really gone.