We have some and in our case it isn't about the timer function but the RFID tags on the cat collars because one will steal from the other two.
I can't speak for anyone else but they kept working for us. Only possible difference I can think of is that we did make sure to put in the optional D cell batteries.
I do not know. However I do have what I consider a good guess.
I think they had to dig up that square to redo something under it like sewer lines or something and the crew repaved just the part they dug up.