Sudden cat flap aversion

[emm142]

We adopted our girl in 2022 and she's about 5-6 years old now. It took a while to train her to use the cat flap initially but she's got very confident over the past few years. All of a sudden today she's behaving really odd with it. Approaching it, sticking her head in it until it clicks to register her microchip, whacking it with her paws, but super reluctant to actually go through it.

She has a tray inside and I'm not worried about that, but she usually loves the freedom to potter around the garden or chase mice in the field out the back (doesn't roam far). She has chased all the local cats from the garden enough that they stay out now so I think it's unlikely a territory dispute (unless it's a new cat in the neighbourhood).

So far I've given it a good clean in case a local cat had scent-marked it but she's still being a bit weird about it.... Any ideas? She doesn't seem injured or in any pain.

Someone might post with something more useful, but it could be just a whim. The sort of whims cats have that other pets don't seem to. I couldn't get my cat to use the cat flap. We tried having one of us on one side encouraging him through, one on the other side gently trying to pass him through. He managed to get each paw on a corner, with rigid legs and heart racing. So we gave up immediately and I was upset that I'd made him so distressed. Then some years later, I was cooking and heard the flap clack, looked round and there he was sauntering down the garden path having decided the cat flap wasn't so bad after all. Hopefully your cat is similar and there isn't something worrying going on.