Vertical line becomes horizontal on opening a saved file in Writer

I draw vertical lines next to the paragraph to indicate changes in the documents using shapes. However, when the file is opened after saving the vertical line becomes horizontal.
I am using LO version and Lubuntu 20.10.
Kindly help in resolving this issue.

How about an alternative?

Edit → Track Changes → Record (Ctrl + Shift + C)

@PKG: this is the first idea which comes to mind. But, when you accept the changes the marks disappear. I am also looking for a persistent solution independent from tracking changes.

@Hitendra: edit your question to attach a 1- or 2-page sample file. Files can only be attached to a question (not possible with a comment).

That might be tdf#122717 - you could try with 7.0.6 or 7.1.3 when they are ready (for testing)…

Yes rectangles also behave in a similar manner.
Moreover, I save the files in .docx formats.
I have experimented by saving in .odt format and this problem does not occur. Hence what @mikekaganski has suggested is probably correct.