How to change orange text back to black in Notes?

Hi folks,

please, see the below example of a Notes entry:

the caret (the text cursor NOT the mouse cursor) is orange (which is the same as the highlight colour and OK).

However, after the data transfer from my previous iMac to the present new one (macOS Sequoia 15.5), random words in my Notes entries are now unchangeably orange while all of the text was originally black. No matter what I do, the words remain orange - even when copy-pasting the text into Pages (where all of the Notes' text appears in black) and then copy-pasting it back into Notes (where then the same words of the text reappear in orange). I would like to have again all of the text in Notes black. How can I accomplish this? And this is not to mention randomly red underlining in Notes indicating a possible spelling error - here: "bottom", which is obviously spelled correctly.

[Re-Titled by Moderator]

Original Title: Blinking insert colour and text