I'm sending post event emails to participants Find Participants> Event Name is> send mail to less than 50). These send fine when just mail body text is included.
I tried the same thing from find contacts- Find Contacts- random search criteria> send to less than 50.
Again, just text works fine, add an attachment and this time I get sent to the advanced search page with this message popping up
Currently Civi 5.19.4 Drup 7.69
Anyone seen anything similar?
Woo-hoo! Just recreated on dmaster.demo
Raised at lab.civicrm.org https://lab.civicrm.org/dev/core/issues/1604