Hi, unfortunately I've run into the same issue a while ago. They should be solving it but we have to wait for a new update of MB.
The problem (at least in my case) il connected to the usage of filters. In particular, if I have empty filters I can't download my results, whereas if all filters are filled then the download arrow shows up where it's supposed to be.
Hopefully this will help you find a temporarily workaround. Personally, I'm either filling all filters or deleting the empty ones from my code.