I had a similar problem with my siemens orion ric aids last year. Actually started a couple of weeks after the trial period, of course. I went back several times and sent back once and they sent brand new ones. Still cut out with a loud noise and sometimes would not come back on even taking battery out for half an hour. Once the problem started it would happen even with the slightest sound. A cough. sneeze car door, dog bark.Even left them out overnight and still no volume. I hated getting a glass out of the cupboard because the slightest tap of it would set them off.
My audiologist finally ask tech support to look into it and they said they didn’t like some of the settings she had made in the program and made recommendations. After following these it has only happened once for a few minutes because of a loud noise but returned to normal quickly. Ask to get a rep involved, they probably will look at the program and change it.
I think it is a Siemens ( Rexton, Sivantos Trex42 etc. ) problem. It happened about a year ago, but I can’t remember what she did.