Vaal mini-boss buries itself forever if pinned, report ID: 2.963.423.238

One of the mini-bosses that appear in the vaal circles in maps/areas has an ability that buries and follows you for a certain time (missed his name twice, sorry). But while playing bone cage/bonestorm the boss remains in the same place forever, never resurfacing again. I am not sure if the pin mechanic is really causing this, but it is the only different debuff that i noticed to be different from the different characters i played.