I have installed a Knight Industrial magnetic door contact on a sliding patio door connected to a Galaxy Flex 50. It's been working fine for a few weeks and in the last week Ive had a couple of false alarms from the contact. First time round I looked at the panel diagnostics and was seeing the resistance fluctuate a little between 1000-1100ohms while closed. I took the contact apart, reconnected and things looked like they had settled down fine. Last night it went off at 2am.. so I disabled the contact. Today I set it to log and chime, and sure enough it went off later in the afternoon and on looking at the diags it stayed open at around 1500ohms (obviously while the door was still closed). I gave the contact a small tap and it dropped back to around 1000ohms. Is it still likely to be a duff connection, or is it a faulty contact? I did notice that when the door is pulled shut hard the contacts do slightly/momentarily knock together, should I open up the gap between contacts also?