Sorry, could never fix it. I just reloaded and lost an hour and did not let Glut join. No fix or option was forthcoming. If you leave him attached, he causes issues later, so its better, just to refuse his help.
Oh good to know. Thank you! I've now defeated Nere in the Grymforge, and so far.... no problems (thogh Glut's picture (dead) is still attached to my Tav picture).
Oh one note: before I arrived at the Grymforge area, I pushed Glut's dead body into the water of the Underdark beach. He didn't disappear (his dead body is in the water). I just left it there, and moved on.