I was there and never witnessed anything remotely like fragging occur but that does not at all mean it never occurred. I'm sure it did and I'm also sure that at least some of those who were on the receiving end richly deserved it.
I did not personally witness the incident but was nearby when a young 2nd lieutenant somehow managed to shoot himsef in the AZZ with an M16.
In Germany 1970 an Army LT1 (who was allegedly undercover CID for Criminal Investigation Division) was walking to his car when a single 45 cal. shot was fired at him, striking the window.
There were several 45 cal. pistols stolen from a company armory, days before. Suspicion was high it was black radicals in the ranks.
There were concerns over race relations. Black Panthers back home, etc.
Not exactly fragging, but very similar. He was not hurt. I never found out the outcome, since I returned to civilian life of family, work and college.
During the 2nd Gulf was a muslim SGT was court martialed for placing a grenade in the tent of his superior. He was Hasan Karim Akbar" a convert from Watts, Calif.
https://en.wikipedia.org/wiki/United_States_v._Hasan_K._Akbar