Bug TextMeshPro bad performance when creating material presets

I have been using TextMeshPro for years in my project without ever needing material presets, however a few days ago I created a material preset for a font I'm using and started to notice massive lag spikes when those canvas were enabled during the game.
I profiled it and couldn't really tell where the problem was


Since I couldn't figure it out I decided to search the commit where this was introduced and it turns out to be the one where I created the material preset:
I created it like this:

BLACKCAPS-Regular BolderOutline is the new material I added.

I deleted that material and voila! No more lag spikes!


I am not even using this material preset on this scene.

So my questions are:

• Did I created the material preset wrong?
• Is this a Unity or TextMeshPro Bug?
• Am I missing something?

Thanks for any help with this.