
I test in my SharePoint Online. But I cannot reproduce the issue.
To troubleshot the issue, you could go to List settings -> Click Highlights column -> Set "Specify the type of text to allow" as "Plain text". Then have a test.
If an Answer is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.