This is just to point out the noise produced and recorded when pressing the button at the end of a recordng.
If you do not see what I mean, just look at the video attached, from ~ 0:45. After each clip, there is this cracky noise when I press the button to stop recording.
I realize it can be quite disturbing to hear that continuously.
There may not be anything that can be done from the manufacturer to fix that. Using a remote control can be an option, but not viable in my case, neither Action 2 nor the remote can be operated for hours continuously.
I am considering removing the last ~ 1 s of each clip before assembling them in a video. A workaround.

Seems to be faulty, unfortunately - you seem to be the first person to report the issue (certainly not a problem with mine).  Having said that, it's standard advice always to shoot a few seconds extra at the start and end of a clip to provide some flexibility in editing etc.

I don't seem to have that issue with my Action 2, but like you and others have said, allow a little extra time for editing in post.