FWIW I can't reproduce this any more either; since 18.04 in fact I've had no problems with gnome-shell crashing. The monitor very nearly always does wake up when it's supposed to now (some difference in the dpms signal being sent? Previously it would always wake for windows and just had a hard time with Linux), and on the few occasions it hasn't, I haven't lost my session and I just needed to powercycle the monitor properly. So I was under the impression this was all fixed. :-) Possibly by not-obviously-related changes elsewhere.
FWIW I can't reproduce this any more either; since 18.04 in fact I've had no problems with gnome-shell crashing. The monitor very nearly always does wake up when it's supposed to now (some difference in the dpms signal being sent? Previously it would always wake for windows and just had a hard time with Linux), and on the few occasions it hasn't, I haven't lost my session and I just needed to powercycle the monitor properly. So I was under the impression this was all fixed. :-) Possibly by not-obviously- related changes elsewhere.