@Jarkes
No, it’s a retcon; S1 Trixie is clearly shown performing object teleportation or conjuration, manipulating the weather, and transmutating matter. Not to a great degree, but doing so nontheless.
I don’t dwell on it, but it’s a retcon.
Honestly Trixie’s magic still isn’t ‘bad’, she just doesn’t use it very much. The main thing is people mostly remember her contributions to TWABA, where no one had magic, and she was still very useful.
Honestly she did better against the big mole thing than Starlight in ‘To Change a Changeling’ (and indeed, Starlight looked rather shocked and impressed).
Trixie’s main problem is her ambition often outstrips her ability. Even Twilight struggled with transmutation and teleportation.