Today I killed the crimson mother twice in the spire of the crimson coin public dungeon and both times it did not count towards the daily endeavour to complete one public dungeon group event.
Confirmed (evening of 2022/09/26). Endeavor credit still failing.
Checked explicitly, and did get credit for the relevant achievement (Crimson Coin group event). Was not expecting any of this to be a problem, so was not paying attention and did not notice at the time whether my character received the skill point for first completion of the group event.
Took the same character to Ghost Haven Bay, tackled the Hadolid Brood Mother, and did get credit for everything (achievement, skill point, endeavor)... explicitly checked for everything, all as expected.
Did Crimson Coin/Crimson Mother on a second account. Payed attention this second time. Was awarded the achievement, did receive a skill point, but (again) no endeavor credit. Did the Hadolid Brood Mother on this second account, and again received endeavor credit.
It is always possible this is something not everyone experiences, or is not encountered every time. But I had the same problem on 2x separate accounts, and seemed consistent/repeatable to me (at least to the extent I was able to "test" for the problem)... such that in future I will probably not bother with Crimson Coin as a means of completing this sort of endeavor.