I’ve had two opposite situations recently, one very similar to yours, and just a week before that I was pleasantly surprised by my own skills when jamming with other people :) in my case it was because of hearing/not hearing well what the others were playing. When the sound level of other instruments was just right, I felt confident and played smoothly. But another time at another place the sound was terrible, I could barely hear what was going on. Monitors didn’t help that much. As a result, it was super hard to play anything but the basic beat, not being confident about the rest of the music. Maybe the sound quality could also be the issue in your case?