Exclude on M2M with F-function not working

[Ron]

I have the following models:

class Activity(models.Model):

user = models.ForeignKey(User, related_name='activities')
project = models.ForeignKey(Project, related_name='activities')

class Project(models.Model):

assignees = models.ManyToManyField(User, related_name='projects')

Now I want to query for all the activities which belog to a user which is NOT in the projects assignees.

My query:

Activity.objects.exclude(projectassignees=F('user'))

Problem is, I always get this error:

django.db.utils.OperationalError: (1054, "Unknown column 'U2.id' in 'on clause'")

Im working on django 2.2.11 and MySQL.

I found a couple of [old django bugs][1] but they are supposed to be fixed since ages.

Any ideas how I can solve my problem? My activity table is huge and I need an efficient way. And I'd be happy to not use raw queries.

Thanks!

[1]: https://code.djangoproject.com/ticket/28551