I guarantee it happened less back in the old DH days, because I remember one of the frequent complaints about old DH press comics was that they were never released on time for all kinds of different titles.
So you are kind of working with a catch 22. Take time and have better untraced art that might slow a whole project by a couple of months time, or cut corners and very obviously trace.
If I remember right Colonial Marines was a series that missed so many timelines/deadlines that they ended up chopping two issues off the ending because it was so hopelessly behind schedule.
The comic just basically ends and everbody was asking about why that was, and DH was basically just like, "Oh, it was always supposed to be that way." Despite it very obviously going from 12 issues to ten issues in the issue count.
Of course there are some artist that don't seem to have that problem, but those same artist aren't going to want to do work on the same title for the rest of their careers.