Just happened to me again too...
7154.652 Sys [Info]: Player unstuck in /Lotus/Levels/KahlMissions/KahlMissionProc/GrineerForestKahlThumper/AOBlRFqSx3EA8oEazAABCAAQAAE.lp in zone /Lotus/Levels/KahlMissions/KahlGrineerForest/GftKahlObjectiveThumper/ at position (-415.511, 1.68672, -53.2524)
Rolling (or rather his dash) and jetpack wont work either, melee will cause Kahl to drop the Kuva Ayanga and have another one in his hand.