As others have said, superadding another style is not the right solution. We need to hear more about what the problem is that is bugging you — in order to help you.
BTW, when you (re)define a style you have the opportunity to specify what should be so about the next paragraph’s styling, I.e. telling Scriv what to do when yu hit Return on a paragraph of that style. Set up another of that style or something else.
Before going too deep into anything further, I would update your copy of Scrivener, if need be. Apple broke the text editor multiple times last year, even before they released macOS 26, which broke even more. We had to apply a number of fixes to keep basic things working. Styles appearing to apply their attributes to the following normal paragraph was one of those bugs.
Yes. I explain how a few post up (now that your thread has been merged.)
But as others said, in your current case that is not the right solution.
The reason I have a basic style is because I’ve been experiencing a bug (explained in the original post). This is the only way I have been able to prevent the bug. I don’t plan to convert large bodies of text to another editor from Scrivener, I just use it for note taking for my dissertation.
I have yet to see a fix for this bug. What’s the move now?
If you know for a fact that you won’t require to compile and reformat whatever you write in those documents, feel free to use a style. It won’t be a problem.
Just configure your style as I have explained earlier in this thread.
POST
You could also test see if having 2 carriage returns after your header fixes your issue.
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If you’d rather fix the real underlying issue, perhaps toggle show invisibles and take a screenshot of one of your misbehaving header plus the begining of the paragraph that keeps changing on its own. Perhaps it is something obvious you’ve done wrong. (Like using a line break instead of a carriage return, and then you would’ve manually reformatted the following paragraph?)