I've noticed an interesting phenomenon. Sometimes a cat's whiskers get curly even in straight haired animals. I know curly whiskers is a usual thing in curly cats but why does it happen in straight haired ones?
Can't say what the reason is but my friend's straight hair get a bit wavy too at times usually after rain. Who knows!
That can happen if they incautiously approach a very hot object like an iron...

We have a cat that looks similar to a Turkish angora. It has been raised as an indoor cat ever since we got it as a kitten and it has always had twisty (curly) ends on the eyebrow whiskers. It had a rather nervous personality and was prone to being mean. Now that it is almost 3 yrs I felt that letting it outdoors in a protected area might help its personality. It absolutely calmed our kitty and he is very sweet now. I've also noticed that when new whiskers come in .....they are straight!!!

Mine loves to sleep next to wall heat vent.

The whiskers on that side of his face are always shorter and curly.

I have a older cat, 17years old. His whiskers are turned and curled in. What does that mean?? I think his health is ailing. He eats well and goes to the bathroom. Has lost some weight tho.