When you copy content from formatted text (e.g. bulleted list) as opposed copying text from a paragraph, and paste it as is (CTRL+V), the pasted content is not the same as the original content, because it includes a block of formatting parameters (span style), which are visible in code. As a result, the pasted content looks OK in the editor and in the published content, but only in the light mode. If you switch to the Dark mode, such text looks highlighted because of those added parameters in code.
Steps to reproduce:
  1. Format some text as a bulleted or numbered list.
  2. Copy some text from a bulleted/numbered item into a different bulleted/numbered item.
  3. View the code (the pasted code contains an additional block that is not present in the original part).
  4. Preview the topic and switch to the Dark mode.
Actual result: The pasted text is highlighted.
Expected result: The pasted text looks the same as in the part it was copied from.
Workaround: You can paste as plain text. Then, you won't have this issue. But also you will lose the formatting.
It is necessary to have the ability to copy formatted text. preserving the formatting and where the pasted part is not modified compared to the original part.
See the screenshots with an example.