What testing regime ? Clearly the new update deployed was never tested, not even once.
C'mon, a blue sreen problem is easily spotted, either manual or automated testing.
Some years ago I uncovered a bug in Seagate's firmware update for their ST3000DM001 HDD. No-one was able to apply the update. I identified the bug, posted a workaround in Seagate's own forum, and made certain Seagate personnel aware of the problem. Four years later the bug was still there. Worse still, the forum had been totally deleted on April's Fools Day.
It turned out that the update was never tested prior to being released. I can confidently say this because the payload files that were bundled with the update package had the wrong filenames. The updater tool expected different file names, so it errored out when those files were not present. The solution was to rename the payloads with their correct names.
ISTM that the testing process must be long and tedious. Presumably some employee decided that a particular change was too insignificant to affect the integrity of the update, so it was decided not to retest the package. I wonder if that is what happened at Crowdstrike.