What happens if Typhlosion uses Burn Up whilst Terastalized Fire?

Question

Hey so I was watching this PokeAimMD video where he said that Typhlosion might get access to Burn Up later in Scarlet and Violet.
If/When this happens and Typhlosion uses it, Typhlosion would become a typeless Pokemon, but what happens if it uses it whilst it is Tera fire? Would the Tera become typeless? Or would Typhlosion be able to spam it repeatably without its side effect?

Comments

I believe Double Shock is functionally the same as Burn Up, except for being a different type. Tera Electric + Double Shock doesn't remove the Electric typing, so it would be pretty safe to assume Burn Up would function the same with Tera Fire. Burn Up can be called by Metronome though, so this is able to be tested.

Answer 1

A Pokémon that has Terastallized (and has a Fire Tera type) will not lose its Fire typing. Therefore, a Terastallized Burn Up can be used multiple times in a row without needing to switch out.

Burn Up (Bulbapedia)

Even though no Pokemon can naturally learn Burn Up in Scarlet and Violet, it can still be called by Metronome, which means this can be tested. The same interaction with Terastallization applies to Double Shock.