Hi @PRINCE, Allison ,
Per my understanding, you are using modern experience in SharePoint Online. If this is not your scenario, please let me know more information about your current situation.
Does this issue occur on all the lists in your site , or only a specific list? Please have tests on a newly created site.
Through tests in different lists, I can’t reproduce your issue in my end. However many users said some similar issues disappeared after converting modern experience to classic experience. You can have a try. And you can open a service request on this issue for more help.
Reference:
https://techcommunity.microsoft.com/t5/sharepoint/can-t-paste-mutiple-rows-into-quick-edit-since-recent-changes/m-p/788054
If the answer is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.