u/choosy_or_boozy

A few days ago my 9 year old cat started going out of the cat flap onto the patio and then immediately going to the window a metre or so away and scratching at it frantically.

He's done this a few times. Usually at night, but also in the day.

I've had him 8 months and he's been regularly using the cat flap for 5. If I go and call him he will come back in through the flap. But it's as if he forgets how cat flaps/ windows work..

Any ideas what might be going on? I tried looking up online but everything I found was for cats scratching to go outside.