Thanks for the replies! They give me a lot to think about!

It is only certain gas stations where this happens, I don't know if I can mention the specific one on here. So I think the company purchased all of the same interfaces. The entire LCD goes blank when you press a button though, so you don't know for a second or two if your pressed key has been accepted by the system. This leads to your pin taking about 10 seconds to enter (security issue if someone is watching).

We are all designers and hobbyists here, so rather than complain, I saw an opportunity to make a better product to sell!

None of the LCDs we use at work have had a problem like that, so I definitely wanted to know if it was something like bad controller selection, or a feedback problem. Either way, it would cause a problem if the displays stopped working altogether in the middle of your transaction.

Thanks again! I will check what happens in the colder months!