Instability during infraspinatus test / 6 months post operative

Hello,

I am currently 6 months post operative from an anterior shoulder stabilisation to repair a large labral tear. Recovery has been good (apart from removal of a proud anchor after 3 months) and I started on easy white water kayaking this week. However, yesterday while kayaking I ended up loading the shoulder badly (in abduction and external rotation, although certainly not extreme) and felt mild pain, and heard a small sound.

There was no pain afterwards but I was extremely worried, so immediately did what I believe is called an infraspinatus test on myself, trying to externally rotate (elbow at side) while applying pressure with my other hand. Doing so I felt my shoulder ball literally moving, with an in and out sensation, with relative ease. I have never experienced this during this motion before, the closest thing I would describe it to is a painless mild subluxation, but surely that couldn't happen in that position?

Anyway, after about 10 minutes I could not longer reproduce this; range of motion is okay but with some pain in extreme abduction/external rotation and during certain lifting movements. Today (the day after injury) I notice the biggest set back is pain during external rotation exercises and lifting even the lightest weight out front. Other things like push ups I can do all good.

I suspect there was some sort of asymmetric muscle firing causing it to slip, as a result of an initial shock, either that or it was slightly out of place for a short time afterwards, thus why I can't reproduce it anymore. I can't find any information about what this could indicate, with the infraspinatus test typically used only as a test of strength, with actual separation not expected to occur?

I would like to know if I have possibly damaged the labral repair, despite the fact there was no disclocation, just a bad movement. The instability during the external rotation immediately afterwards has freaked me out and is certainly not normal. Any thoughts on this would be great, it is hard to find information about this particular symptom.

(By the way I am very dedicated to my physio exercises, making sure to do these at least 3-4 times a week along with introducing swimming and other dynamic exercises to encourage strengthening. I have had successful repair of my other shoulder over 2 years ago, thus I am not new to this experience so I do not ask this question on a whim).

Thank you very much for your time,
James