Today i entered the car and when i closed the door the hazard lights flashed 3 times in rapid succession. I opened and closed the door repeatedly and the same result. The car then wouldn’t start. “ key not detected”. I locked the doors via the fob and then unlocked the doors. The car returned to normal. Anyone else ever see this happen? Hopefully nothing serious is brewing up.

Start with the key batteries. I find with the KESSY system they last about 2 years so now they get changed at the 2 year point. Or were the keys on a cold windowsill? How is the spare? There is an optimal position for the keys on the centre dividing tunnel, rather than in your right hand pocket. Foil from sweetie packets around the key?

Beyond that it all gets a bit expensive..

New battery in the key couple of weeks back. The key was in my pocket. Definitely seemed like the car glitched.

Key in pocket can sometimes not be detected, another issue can be where your mobile phone is in relation to the key

I get "Key not detected" every now and again in my Skoda

Same as @Stonekeeper above, it happens to me very occasionally. I don't worry about it since I won't place the key in the car and risk jumping out without it (self-locking risk, etc). I always keep it in my right pocket. Batteries are replaced regularly, plus I rotate the 3 keys every 4 months.

Once in a while my car has a hissy fit, not unlocking upon approach.Always opens when I touch the handle. I try spare keys (with new batteries) and and they're often erratic. Also I've noted if you approach car with keys held with phone (or something large or metallic) car probably won't unlock. Weird