Haven't seen this, no.
Ok, I saw one Err80, last night. I'm just over 2500 shutter actuations. Simply power cycling the camera (not removing battery) resolved it. IIRC, it occurred at power on just after changing lenses (I think it was the 24-105L that was mounted). I was doing AFMAs, taking lots of shots in quick succession and changing lenses frequently. I took a couple hundred shots before it occurred, a couple hundred shots after it occurred, there was just the one error. Hopefully a one-time event, but we'll see.
Some of the posts on this are linking this to lens mounting, mentioning AF motor lockout, etc. The AFMA zeroing-out bug is also related to the camera not properly recognizing a newly-mounted lens as one that was previously mounted. Is this a theme of buggy firmware code for lens recognition?