Good question.
>Ditto is the only Pokémon to date with a catch rate of 35. However, prior to Generation V, if Ditto transforms into another Pokémon, its catch rate will become that of the new Pokémon.
So to answer your question no, Ditto's catch rate will remain at 35 if it has transformed into a different Pokémon in Generation V onward. However prior to Generation V yes, if Ditto transforms into another Pokémon, it's catch rate will become that of the new Pokémon.
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It is the same case for Transform as in Generation I to IV if a Pokémon uses Transform it will copy the target's catch rate. However in Generation V onward Tranforms no longer copies the target's catch rate.
>Transform no longer copies the target's catch rate.
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