the thing is, a really good joke has at least a little bit of transgression, and every single sharp edge is carefully sanded out of these AI things in order to make it into a shiny marketable product... I think it's literally impossible for it to be funny on purpose to any reasonably intelligent adult
I think the last truly funny thing an AI has put out was the bottomless pit greentext:
and I think it was only funny because it still had a little bit of edge and had human input steering it into a funny direction... also, the quirkiness of the text, all that weird repetition, only contributes to make it funnier, so it's not entirely on purpose
I believe that humor is beyond the capabilities of AI now and for the foreseeable future