Elk keypad stopped registering keyfob access


We have a prox reader wired to an Elk keypad, and have a rule set up:

Output y is a relay controlling an electric door strike. Earlier today (while I was away from the office unfortunately), it just stopped working. I got in and ran my keyfob across the prox reader several times, nothing happened. I went to the Elk panel and manually shorted the output contacts with a spare bit of wire, and the door triggered. I then went into the output control menu on the keypad, turned the output on and then off (which triggered the door), and now the keyfob works again. Has anyone ever seen anything like this? Any idea what happened? Is it likely to repeat? Looking in the Elk log, it appears it just stopped registering keyfob access events. I'm running the latest Elk M1G and keypad firmware. Using a HID prox reader.
all HID readers beep on the initial reading of the card regardless of the access control status. Is the reader beeping when you present your card?
Also pe sure that none of the other wires are shorted together or grounded. If they are safe them off and cycle power to the reader and try it again.
If it does not beep then the card is bad or the reader is bad. Try another card or try the card on another reader (at work or something...)

HID has had some problems with Readers, mainly the Thinline II series.
The reader itself was beeping, the keypad just didn't register any access events. When I went into the automation menu and toggled the door strike there, then exited the menu, the keypad began registering keyfob access events again.