Have used quite a few of these basic little switches with good results.
Have installed on in a new site for tagging and the first had failed, I thought, but testing on bench after reprogramming it appears not.
The second switch has done the same thing, which is effectively freezing.
I power down and restart and it is fine for days.
I have inserted a Conditioner in The PSU socket but it still does it occasionally.
Does any one know if they are Sensitive to mains or data line interference .
Cheers
Des