Multi-select does not work in any of the Sharing Center tabs. There are checkboxes next to each shared item and an Action dropdown to affect all selected items, but it is not possible to select more than a single item (unlike any other area of LastPass with the same UI elements). Multiple items cannot be selected either clicking checkboxes one at a time or by holding the shift key, both of which work elsewhere.
LastPass support claims this is an as-intended behavior, however I find it very hard to believe this behavior is truly an “as-intended” situation as it does not function as implied by the very clear UX/UI design cues (checkboxes, dropdown menu for operating on multiple selections) and does not function the same as other areas of LastPass with the same interface.
The lack of multi-select in the sharing area also effectively cripples family sharing without being forced to utilize shared folders, which requires the complete reorganization of a vault with over 1K entries, which in turn hamstrings the ability to share passwords with multiple different family members without creating independent copies of the same entry.