Opening saved LibreOffice in Microsoft Office causes green underlines!

Hello,

I installed LibreOffice yesterday for the first time as I don't have Microsoft Office installed yet in my system. I wanted to try out LibreOffice as an alternative.

However, I am experiencing a big issue. I have my own CV, which I normally save in Office 2010. When that same CV document is opened with LibreOffice and then saved, without doing anything to the document.

I then tested on my dad's Office 2010 by opening my LibreOffice saved document and my CV ends up opening with all these green underlines.
Here's a printscreen. I removed my name, email and phone for security...

Basically, I want to be able to save the document in Libre. But as I open this document in Microsoft Word, you can see all these green underlines.

For some reason LibreOffice is saving the document and messing it up in a way so that Microsoft Office thinks these are spelling and grammatical errors.

Is there any way to fix these errors? Also it's not just the green underlines. I am also getting red underlines for the names of the Employment history where ignore all and saving in Libre doesn't work. Reopening the document returns back red underlines.

Opening the same document in LibreOffice doesn't cause the green underlines, but opening any saved document in LibreOffice and then opening in Microsoft Word triggers green underlines.

I'll be grateful if someone knows the solution to this problem!

I have tested original word document it is in UK language. The same for both LibreOffice and Microsoft Office 2010.

If I save the document in MS Word and the original document in my PC from Word 2010, no problem and no green underlines.

The moment I simply save in LibreOffice even without editing any of the fonts, words, etc this will trigger underlines when opening it in MS Word.

It seems like I might not have a choice but to install Microsoft Office. Because any saving in LibreOffice triggers underlines and red underlines.

If I edit the document in Microsoft Office and click ignore all and then save changes, it works perfectly! I can then reopen the same document in Microsoft Word and neither green underlines or red ones will show.

This is the same document that I originally created under my PC in Office 2010. That document has no issues when opened under dad's PC as it is originally in Microsoft Office.

Somehow saving the document in LibreOffice triggers these squiggly green and red underlines in word. Same document in LibreOffice does not show these squiggly green lines and does not detect grammar and spelling errors.