Hanging Pikes and Shoulders

I subluxed my shoulder perfoming hanging pikes this morning. I never had this problem while performing them before and I’m wondering if it’s just a result of one bad rep/poor form or is there some inherent shoulder instability associated with the exercise. I’m doing the ABBH program right now. Any suggestions on what I can substitute for the hanging pikes?

Would lower pulley crunhes on a swiss ball be a good alternative?

Maybe use an arm harness and continue to do the pikes.