Gray "highlighting" surrounded by square brackets in text boxes

Word can indeed be perplexing, but I am convinced empty paragraphs are at the root of much of the evil (don't get me started on Click and Type).  I see users leaning on the Enter key or the space bar to get the cursor where they want it, and I have to leave the room.

OK, there are a lot of other issues too, many because of defaults such as automatically updating document styles, and Word guessing which style is wanted, and oddities with tables, and so forth.  But I have learned to tame Word (mostly) by turning off most automation and through the use of named styles, and am actually super impressed with what lies beneath the surface of the default automation.

It does look like a content control.  I created a plain text content control, which looks the same.

However, unlike a content control, there is no option to remove it.  Also, it is always shaded gray, not just when selected.  

If I delete all of the text in the text box I am left with an I-beam cross-section: 

This seems to be the surrounding brackets I described earlier, but they have changed places and are now back to back.  By the way, what appeared to be a pipe character, as shown in the second image in a previous post, turns into the I-beam when all of the text is deleted.

The strange thing is that neither the original document nor another copy have this same issue.

Here's another curiosity:  There is an I-beam at the start of a paragraph, not in a text box.  It appears at whatever paragraph is used as the graphics anchor for a particular text box.  So far it appears there is only one in the document.  

Maybe it's the ghost of frames, or something.  I don't have ready access to a OneDrive folder or similar, other than my work one.  I realize they are secure, but even so I am reluctant to post a link to a document in it.  However, later today I can set up to link to my personal one from work, and post a link to that if you think seeing a document with the issue would be helpful.  I'm about ready to write this off as an anomaly, but am still curious.

While you were replying to me I was replying to Antonio.  There are some examples posted in that reply.  It turns out there are at least two versions of the anomaly.  

I looked at the link long enough to know it wasn't relevant to my issue. 

As I mentioned, the document I copied didn't have the issue, nor did another copy I made.  I'm pretty sure I opened the original and did Save As in both cases.  I know I did it that way the second time.  This inquiry is just because I don't like it when my documents do things I didn't authorize and can't identify. 

Just to repeat, this is only in text boxes, and it is in all text boxes, many of which I never touched.  If it matters, the original version of the document may have been Word 95, although the version from which I copied was almost certainly at least Word 2000.

I can't post the document due to its proprietary nature, but if it helps I may be able to post a document with representative text boxes.

Excuse the misunderstanding and I'm really sorry, I ran out of ideas

Kindly regards...

Hi bamoob, I'm Antonio, an independent advisor, not a Microsoft agent. First, which means that I am a fellow forum users in the community just like you, and will be trying to help you.

So in this case, I hope we can have an understanding from the beginning to avoid misunderstandings.

This link may interest you

https://docs.microsoft.com/en-us/office/trouble...

If you still cannot find the solution, you should take into consideration that you have a defective document due to download or that it is infected with a virus or malware.

Since this error is not a common problem.

I suggest that if the error persists, feel free to send an image of the problem, so we will have a better vision to find the solution.

Kindly regards...