Pretty common I think.

Not only hiring. A coworker was blocked from organizing some technical community event because among the 5 speakers who applied to present only one was "x".

I get the sentiment behind such quotas but it's not always realistic. I think a fair way to look at it is, if the environment is such that "x" are discouraged from participation then it needs fixing. But it should be easy for the diversity team to go identify such an issue and tell the organizers to fix that rather than saying "meet quota or no event".

For hiring, it's fine to look at numbers and identify a skew pattern and to look into why it may exist and how to counter, but just asking for percentage alone is not helpful.