Teen at 0 lb?

My Ura Young Violetchi's current base weight is 0 pounds. I'm so confused.

Is this how it's supposed to be or is it an individual glitch?

It's a glitch.

I don't know of a fix without resetting the Tamagotchi.

If it doesn't pose a problem to playing with it I assume it should be alright

It's a common glitch on the V4 and V4.5. Resetting and downloading it like misuzu_kamio said will probably fix it. Other glitches to look out for are the name altering glitch and the pile of pixels for a mate glitch. The name glitch won't harm your tama (neither will the weight glitch) but I've heard the pixels for a mate glitch will so beware of that one. (Interesting fact: the V4 and V4.5 have been called the tamas with the most glitches).

Hmm... Ichigotchi's base weight on the V4 is 0 pounds, so I wonder if that's Ura Violetchi's base weight on the V4.5?

I'm sure it's nothing to worry about, even if it's a glitch. If anyone else has had an Ura Violetchi weighing 0 pounds, it's probably normal.

It's probably a glitch. Try feeding it and see if it gains weight.