Want to know if anyone has seen this issue and what solutions are available.

I was testing the emergency light and found it not working, but when I turned the main line power on it works. Had both 110 and the main line off. Thought it might be floor, so I tested the one next to it and had the same result. I recently tested a third Tac-20 with the same results. A friend of mine tested one and did not see the same thing, but he said he lost all power when turning it back on. (Likely unrelated) Any feedback would be appreciated. Normally I do not turn the main power off while testing emergency lights. So this is new to me.