I had issues with three Thrunite lights.
The first was a faulty emitter in a TN30, they swapped out the light immediately, even before I sent the defective unit back.
The second was a TN11. The edges cut into the body were too sharp for my liking, and they upgraded me to a TN11S
The third was a switch problem with the TN11s. They sent me a new switch.
Communication about the switch was a little challenging (English, clearly was not that person's first language) but once there was a clear understanding, there were no problems.