I did a search on the forums but couldn't find any threads pertaining to this problem. Forgive me if this has been answered before.

For the past two weeks or so, sometimes when I go into my room I find my male CT betta 'Bowie' sucked up against the intake for the filter. Naturally I associate this behaviour with unwell fish that are weak, however if it's feeding time Bowie will cheerfully unstick himself to gobble up his dinner. On other occasions even tapping against the tank won't get him to swim away. I've turned off the filter to allow himself to swim away, sometimes he does, other times he just hangs there.

Is it possible that he's just chilling out there? Bowie is normally a very feisty fish (that's why he has a 5 gal Eclipse Hex all to himself) and has even attacked my hand in the past. I do a 40-50% WC at least once every 10 days, sometimes more often. My water params. are good, temp is set to 78F. I see no signs of fungus or parasites, his poop looks normal and, as stated before, he has no problem munching his 4 or 5 Hikari gold betta pellets twice a day.

This has got me stumped. Any suggestions?

Betta massage?
Mine sit in the outflow from my HOB's and get a massage from the water falling down, but I have heard of them getting their kicks from the intake. Check for scale damage to make sure he's not getting "hickeys". Otherwise, I say he's probably fine... just keep an eye out for anything else wierd for awhile.

mine usually swim away from the filter intake but they like to hide behind a lot

Hello Nottingham, long time no see.. welcome back.
I agree, I think he may just like how it feels.
If you are concerned though, you can cut a piece of sponge,and put it in the intake, which will keep him from being sucked too hard against it. And help prevent scale damage or hickeys. (it will also grow more beneficial bacteria, lol.)
Other than that, it seems to me as if he is fine.