Hi,
Issues of Word online are not supported on Q&A at current, I suggest you post a new thread on Microsoft Answers Community: https://answers.microsoft.com/en-us/msoffice/forum/msoffice_word?sort=LastReplyDate&dir=Desc&tab=All&status=all&mod=&modAge=&advFil=&postedAfter=&postedBefore=&threadType=all&isFilterExpanded=true&page=1
The reason why we recommend posting appropriately is you will get the most qualified pool of respondents, and other partners who read the forums regularly can either share their knowledge or learn from your interaction with us. Thank you for your understanding.
I personally suggest you check whether this issue persists if you paste content to other location, for example: Notepad. If not, this may be an issue with LMS. You may look for a setting similar to Office Smart Cut and Paste.
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