I created an Ascended Hunt Swamp card and played it. The realm loads fine. I was grouped with my husband. Both of us experienced no damage when attacking creatures. Any weapon we used had no effect. We left the realm and I reset it. I even made a new card and we still experience the same issue. I do not remember the minor realm card but we did not change it.
The ascended hunt realms often start up with a Hunter Eminent minor card active, which makes all non weak spot hits deal no damage.
Change the minor card to something else and you will be able to damage enemies with non weak spot hits again.
This is not a bug, it is intended.