Why did Ditto transformed into Cinderace had its G-Max sprite, but not Max Moves?

Question

Once during a Gen 8 AG battle, the opposing Cinderace became G-Max and took my Yveltal by using Max Flare.
I sent out my Ditto and with Imposter and it transformed to a G-Max Cinderace's sprite but had moves as normal moves (i.e) not Max Moves.
Why did this happen? Is this a glitch?

This happened in Showdown.

Thanks in advance

Answer 1

Your Ditto must have Tranformed to the sprite of G-Max Cinderace but not Gmax Cinderace.
It is evident from

If a Pokémon transforms into a Dynamax Pokémon, it will successfully
transform but not become Dynamaxed. Transformed Pokémon can Dynamax,
unless they are transformed into Zacian, Zamazenta, or Eternatus.
Transform does not copy the Gigantamax Factor, so even if a Pokémon
transforms into a Pokémon that can Gigantamax, the transformed Pokémon
will be able to Dynamax but not Gigantamax. If the target is Eternamax
Eternatus, the user transforms into the regular version of Eternatus.

So your Ditto would have just copied the Sprite.

But still its very abnormal for this to happen. Itwill become just a normal Cinderace as stated abovein the case of Eternatus.

See this Battle to see what actually happens when you send out a Ditto during opponents Dyanamax.

Hence it must be a Glitch

Hope I Helped

Answer 2

If a Pokémon transforms into a Dynamax Pokémon, it will successfully transform but not become Dynamaxed. Transformed Pokémon can Dynamax, unless they are transformed into Zacian, Zamazenta, or Eternatus. Transform does not copy the Gigantamax Factor, so even if a Pokémon transforms into a Pokémon that can Gigantamax, the transformed Pokémon will be able to Dynamax but not Gigantamax. If the target is Eternamax Eternatus, the user transforms into the regular version of Eternatus.

I'm assuming that even tho it transforms into the dynamaxed mon but not dynamaxed itself, that's the reason it doesn't have max moves as those can only be used in a dynamax state

Source: https://bulbapedia.bulbagarden.net/wiki/Imposter_(Ability)