I’ve been using a Leica R7 for a couple of years, and it’s been great. The electronics still work perfectly without any issues, and it operated flawlessly until a few days ago. Now, the film advance mechanism gets stuck (also the film roller) , and the film can't be advanced to the next frame. The only way to disengage the knob and allow the camera to fire is by pressing the rewind release button. However, even then, the film doesn't advance. It’s similar to the technique used for double exposures in manual cameras.
I uploaded a short video on YouTube that can show it. https://youtu.be/tWVVDBjmSfE