So If I make a shared mailbox, right-click on it, and 'Manage Full-Access Permissions'. I click 'Add', and procede to search and add a user. I do this two or three more times with different users I want to be able to access this mailbox before clicking 'Manage' and finalizing the process. Exchange claims that everything completed without issue. I click 'Finish', closing the window.
I wait a few moments.
I go back into 'Manage Full-Access Permissions' and low and behold, there's only the very last user I added in the list.
If I add users to the list one-by-one finalizing the process each time it works as expected. I only have a problem when I try to add more than one at a time.
I'm very perplexed about this, and I've found nothing especially useful about it online. Any assistance you could offer would be appreciated.
EDIT: This problem does NOT present when performing the same process in 'Manage Send-As Permissions'. Weird.