Procedure is definitely a better word for "strictly defined process".
I've no problem with that. Making it up is a little harsh, but the absence of friction to change is one of the markers of agile.
Regarding bugs: That thread has a whole lot of confused thinking in it, imo. An experienced dev can differentiate a bug (in a done story, say) from feature creep pretty quickly. And, as before, I'd expect a team to fix a bug, whereas additional features usually go into the backlog, etc.
That behaviour can go all out of whack when agile has been subverted, though; when, say, velocity gets used as a performance metric, or there's a blame culture. No team wants to leave known bugs unpatched, and throwing them into the backlog just creates more 'busy' work.
In addition, if a bug is proving hard to fix, then it indicates a possible bigger problem and bears investigation.
In general, but the order has dependencies. So it's quite possible for a new bug to jump to first place.