I'm on version 3.14.19312.0 and have the same issue. Adaxes can no longer display the full access permission (group) on an Office 365 shared mailbox. It will display the Guid for Send-as (same group as used for full access), and nothing for Full access, when you try to add the group under full access you get an error saying that the group cannot be found in M365.
Here are the Exchange trace logs:
[07/20/2023 10:35:25] Selecting an Exchange server for the organization 'Org'.
[07/20/2023 10:35:27] Connected to XXXXXXXXXXX. MaxRunspacesCount: 10
[07/20/2023 10:35:25] Get-RemoteMailbox -Identity "CN=SharedMailbox,OU=Shared,OU=Resources,OU=Exchange,OU=Services,OU=Resource Management,DC=ORG,DC=nz" -DomainController "XXXXXXXXXX"
[07/20/2023 10:35:27] Succeed
[07/20/2023 10:35:27] Get-CASMailbox -Identity "ca49e2c5-022c-4268-8993-cbc84719c687"
[07/20/2023 10:35:27] Succeed
[07/20/2023 10:35:32] Get-MailboxPermission -Identity "ca49e2c5-022c-4268-8993-cbc84719c687" -Owner "True"
[07/20/2023 10:35:32] Succeed
[07/20/2023 10:35:32] Get-MailboxPermission -Identity "ca49e2c5-022c-4268-8993-cbc84719c687"
[07/20/2023 10:35:32] Succeed
[07/20/2023 10:35:32] Get-User -Filter "Name -eq 'SMBX_SharedGroup_FA'"
[07/20/2023 10:35:33] Succeed
[07/20/2023 10:35:33] Get-Group -Filter "Name -eq 'SMBX_SharedGroup_FA'"
[07/20/2023 10:35:33] Succeed
[07/20/2023 10:36:34] Get-MailboxPermission -Identity "ca49e2c5-022c-4268-8993-cbc84719c687" -Owner "True"
[07/20/2023 10:36:35] Succeed
[07/20/2023 10:36:35] Get-MailboxPermission -Identity "ca49e2c5-022c-4268-8993-cbc84719c687"
[07/20/2023 10:36:35] Succeed
[07/20/2023 10:36:35] Get-User -Filter "Name -eq 'SMBX_SharedGroup_FA'"
[07/20/2023 10:36:35] Succeed
[07/20/2023 10:36:35] Get-Group -Filter "Name -eq 'SMBX_SharedGroup_FA'"
[07/20/2023 10:36:36] Succeed
[07/20/2023 10:36:36] Get-Group -Filter "Name -like 'SMBX_SharedGroup_FA*'"
[07/20/2023 10:36:36] Succeed