I have never, ever seen this before. I don’t even know how the table was created with a different collation. However, I had all my other tables created with the character set utf8, no collation specified.
I had to convert the second table to match the character set. This probably wouldn’t have been a problem if I wasn’t joining on a character field.
alter table exclusion CONVERT TO CHARACTER SET utf8;
First time I’ve ever seen that one.