These are the words of Cece, the Foreign Director of Aston English.

"For the temporary stay permit, as we mentioned before the new policy, for now, not only in yinchuan , but in other
cities are the same situation. Z visa could not change to L visa any more, for this , I double checked with our xian Aston
foreign staff officer,too."
"It is a new policy, before z visa could transfer to l visa ,but new policy only could transfer to a stop permit."

You are correct by saying you've never heard of a Humanitarian visa. I couldn't find any information regarding this visa either. Aston Yinchuan is using the local PSB as a play-ball. I'm waiting for the outcome of an investigation and will keep you updated.