How did my Vaporeon change nature?

I’ve had a lot of problems in this playthrough. So basically I beat Giovanni and was on my way to victory road without healing because my memory is like a goldfish and I forgot to heal. I totally forgot about the rival battle and got defeated. I defeated him on my second try and went back to heal this time. I looked at my stats to see if I needed to train before Victory road. I 100% remember having a timid nature for my Vaporeon, as I wanted a minus attack nature for Vaporeon and was hyped to get it. When I looked at my stats, Vaporeon had RASH nature, which I’m not complaining about but still. Is this a glitch or did something happen during the rival battle. I’m nearly 100% sure that you can’t change nature in Fire Red. So why did this happen?

Pleaselog inorregisterto add a comment.

There are only 2 options to this. You either didn’t remember what is was properly, or it glitched out.I did my research, and there are no nature changing glitches as far as I can see. So, you could have glitched your game out in a way that barely anyone has done, or you forgot the original nature of it before and when you saw that it had a rash nature, that was actually the nature it had all along.If you are absolutely sure it was timid before, then you must’ve glitched your game. It is a GameBoy Advance, not the newest console, so you probably just glitched it.

Hope I helped!