I had request GMM Culture of Blood on 3 characters. The first step I put all 3 characters on the trigger spot at the same time and got the yellow text on each screen, but only 1 updated their task. I was unable to trigger the other two after that so I completed the task on the character that updated. I went back to try to trigger it again on another character but it was not going even though I thought I was standing on the trigger spot. In an attempt to reset it to try again, I deleted the Bloodmoon Disguise, dropped the task, got rid of the disguise, and got a new task. As much as I tried I could not get the first step to trigger again. During this, I noticed that the disguise was not working and I was getting attacked by the orcs in that spot. I even tried going to a new pick but it would not start. That was yesterday evening so I tried again today. I was able to get the task going on the remaining two characters. From my end it looks like it bugged out and it took 6 hours for it to clear on the other characters or otherwise reset in the zone.
I did not look, but it worked on 1 out of 3 the first time before bugging on the other 2 in the first zone I was in. If I remember the pick was closing shortly after I got into it but still didn't go when I got back to the base zone.
I just realized a part from the description I forgot in all the commotion. The task does say that the disguise only works during the day. It must have gone to night but I did not realize because it doesn't seem to get dark in the dome.