I think part of the deeper issue is that contributing to an OSS project has become a rite of passage, a way to strengthen your profile. If you need to have contributed to look good but you don't really care about the contribution itself then you resort to this kind of trick.
We had a similar plague for vulnerability disclosures, with people reporting that they had "discovered" vulnerabilities like "if you call this function with null you get a NullPointerException". D'uh.
There is also the fact that we're measuring the wrong thing like speed of development. In my previous employer people had jumped in fully into the AI bandwagon, everyone was marvelled at how fast they were. Once I was reviewing the PR and I had to tell the author "dude, all your tests are failing". He just laughed it out. Everyone can produce software very fast if it's not required to work.
AI-assisted gamification.
Indeed. I have been receiving clearly AI generated job applications out of the blue and they tend to point to their contributions to github projects so some of these must be getting through.
Someone somewhere once decided that it was a great idea to add how many github stars a project that you have contributed to is a useful metric during the hiring process and now those projects get swamped with junk.
"I can do math really fast"
"okay, what's 137*243"
"132,498"
"not even close"
"but it was fast"