ESLint: Mixed spaces and tabs

Hey there,
I'm trying to write a VueJS App.
Inside the .vue files and there only in the script sections when trying to write an if statement or a method for example it sometimes randomly switches from tab indent to space indent.
The error, mentioned in the title of this post is shown and the whole App wont run until this is resolved.
Worse even:

Deleting the "space-tab" an trying again with a "real tab" won't do.
Often times even deleting and hand writing the whole method again won't even resolve it, it enforces a space indent. No matter how I try to make it a tab or try deleting the spaces

The next "random number" of methods that I'll be coding will have normal tab indent and if I'm super lucky I can then resolve the issue after having written another couple lines of code.

Super weird and random behaviour.

Last week, I tried a little reactJS and had no issues there so it seems to be a thing with vue or a problem that at least the linter only sees in vue.

Hope you guys got an I idea. I'm relatively new to webstorm, coming from an simpler Editor and really have no idea how to resolve this

Thanks alot