Yes, I had one of these yesterday - part of a comment had been
cut-and-pasted from Word, and contained something that looked like an
ASCII minus but was in fact an em-rule.

Whether you get a failure or not, and at which point of the process,
depends, apparently, on all sorts of things, including in particular the
connection character set. In our case the procedure had been stored in
the database OK, and the application ran OK, but developers couldn't
extract metadata from the database using Database Workbench or (to a
more limited extent) FlameRobin.

I decided that the best way out of it for me was to replace the em-rule
with a minus.

--
Tim Ward