Shortcode not parsing properly

Hi

I’ve got the following shortcode in my Single Event Page Format:

[events_list limit="3" category="#_CATEGORYSLUG"]

Until recently (possibly when I updated to 5.8.1.2) it was working perfectly, but is now displaying “No Events”. If I remove the square brackets it correctly displays events_list limit="3" category="comedy", and if within the shortcode I change #_CATEGORYSLUG to simply comedy that lists three ‘comedy’ events. But dropping the #_CATEGORYSLUG attribute into the shortcode no longer appears to work.