I have several groups where, under Group Settings, have "Group Managers and Owner can contribute" selected for Who can Contribute Content to this Group. However, as a group manager I am not able to share into this group when sharing from my Content. As an AGOL administrator, I have set the role for this account to be able to share content to groups. For groups with the setting selected to allow Group Members to contribute content to the group, I am able to share content like normal.
I did notice that I was able to successfully share this same web map into the group with the above listed setting (Group Manager/Owner) from the Map Viewer > Share > Choose who can view this map > Members of these groups.
Is there a bug to where the setting for only allowing Group Managers and Owner to contribute content to the group is not being honored when sharing from the Content tab? Many groups in my AGOL Org need to maintain this setting (and not to allow all group members to contribute) for group content integrity.