It is most certainly a bug with ghostman-pathing(anytime your character's silhouette appears to show you where your action will take place.) If you are interrupted by AoO when using ghostman-pathing, your action can be nullified and spent. Happens every time for me, but that could be anecdotal.
When you ghostman-pathing to attack, I think that sometimes your character will reposition themselves when they go to animate the attack. They enter the enemies reach where you stated you wanted to attack, but during the reposition, they slightly move out of the the targets reach, triggering AoO and canceling your attack. This may not be the case, but that is my best guess at what is happening under the hood.
