After highlighting text in body of email it gets unselected [ gmail ]

When reading a post in gmail if I highlight some text in the email body a split second later that highlighted text somehow reverts to being normal text not highlighted so I have to highlight same text again ( I am trying to copy text from gmail post )

This happens across all browsers when reading gmail

How to shut off this behavior ?

I am doing this highlight of text manually with the cursor nothing automated here … this bad behavior in gmail started a couple years ago however previously it was never an issue