The Green Arch was the first serious climb Miguel Carmona and I did on Tahquitz. We did the route way back in the summer of 1980. I remember the first pitch had some 10 A climbing to the base of the Arch. Miguel led the Arch on some very old fixed pins (Knifeblades and small angles) and his set of wires and RPs. When he reached the area where you have to exit the Arch and go right and up, he slipped, pulled all the pro (including the fixed stuff) and took a spectacular fall straight down onto my belay. I stopped him about 10 feet above me. I was more freaked out than he was, because after many four letter words of frustration, he went back up there (without those pins) and climbed the Arch cleanly. I had a very difficult time getting over the end of the Arch even on a top rope. That was one incredible lead especially after a very long (45-50 feet) fall. Unforgetable.
One of the times I did it, my old friend Brent Ingram cleaned the pitch. When he arrived at the belay he had with him the gear I had placed as well as several “fixed” pins I had clipped (which he had removed by hand.) When I looked at him quizzically, he said “well, the second is supposed to bring up the gear, is he not?”
I suspect that due to the intense sun exposure that route gets, there is a lot of expansion/contraction in the crack which loosens the fixed gear.