Tominator

This is a 1998 with a manual tranny (if that matters).
When you lock the car with the fob, you can immediately unlock & get in as usual, no problem.
If you lock it with the fob, go away for a few minutes, then return and unlock with the fob, you can open the door, but the alarm sounds until you hit unlock on the remote again. Weird.
Replaced the battery & re-matched the transmitter. Same results...
Any ideas?
Thanks!!!