InDesign 15.0.2 , Mac OS Catalina 10.15.4

I've been provided text to put into document. Copy pasted in (stripping formatting), added Paragraph Formatting (basic paragraph), then selected text to make it a numbered list ... and it numbers every item as number 1.

I did my own list, and it worked fine (1, 2, 3).

I copied the text from within the document into the new correct list, it reverted all the numbers back to 1,1,1.

I retyped the text to keep the correct numbering - that fixed the issue for me.

I've attached a video showing what happens when I apply the formatting. This is simply setting up the numbered list via the type menu, but put into the paragraph style for quick access.