I am having some issues with copy/pasting in the InDesign 2021. I am guessing it's related to the update, because I never had problems before and I created the document I am currently working in, in a later version. When I use copy/paste, not matter if it's a single letter or an entire paragraph, it automatically converts the entire section to the destination style. Extremely annoying. I am copy/pasting bits of text that have already been formatted and assigned paragraph and character styles. But it also happens with text bits from other programs. What to do??
If you're not pasting into an existing frame and instead pasting and creating a new frame, more than likely the text is using your InDesign defaults. In your document, with nothing selected, open your Paragraph Styles panel and look at the style that is chosen. That's probably what is controlling your formatting. Choose Basic Paragraph or some other style to reset the defaults and try again.