How common is it in papers to contain copied paragraphs from previous papers? How common is for good and high quality research papers to contain 1 or 2 paragraphs of copy paste from previous papers of the same researcher?

Is this common or it's a red flag of low quality research?

Edit: 2 papers from the same researcher tackle different problems. To solve each of these problems some sub methods are used. On paper A sub methods 1, 2 and 3 are used. On paper B sub methods 3, 4 and 5 are used.

Sub method 3 is copy pasted (exact same explanation) on both papers A and B. The newer paper (B) makes no reference to paper A. The papers have nothing in common, aside from using this sub method.
As a user of papers I strongly prefer copy-paste to rewrite for the sake of rewrite. It takes a lot longer to see if there are any differences in the method between the papers if the descriptions use different words.

That said, it seems to me that the later published paper should reference the earlier one.