You should turn "all beeps on" while you test this. It could very well be that your dash cam is cutting videos short by 10 - 20 seconds. If your beep settings is only for start-up, you will not get the beeps while driving indicating you have a problem.
Incidentally, I recently started to get a single beep occasionally with my Samsung Evo Plus 128 gb sd card. - - I thought the cards solved my problem, but apparently it didn't. However, I only get the single beep once in a long while; with my other cared (Lexar) I was getting the beeps frequently.