UPDATE - I have received the confirmation from the support/engineering team that this issue is now resolved.

I have received the confirmation from the support/engineering team that this issue is now resolved.

Yes, as mentioned above in my comments, we raised a formal ticket with Adobe Support. They were able to replicate the issue across the users in our org. 

Update -Following workaround provided by the support team -1.Save/exit seems to reset the ability to add more segments to the drop down and the operation is successful.2. While adding a second option in dropdown (before the dropdown freezes) - Select all the segments at one time and drag and place i...

Update -Following workaround provided by the support team -1.Save/exit seems to reset the ability to add more segments to the drop down and the operation is successful.2. While adding a second option in dropdown (before the dropdown freezes) - Select all the segments at one time and drag and place i...

For my team, it's happening across the browsers - all conditions.

Issue -Earlier we used to add multiple segments as options in a segment dropdown.But since the new changes have been made, where we can select multiple segments (as OR condition) in a segment dropdown, I am not able to add more than two segments in a dropdown.Even by pressing shift, it doesn't work....

UPDATE -Met with support team, there seems to be an engineering bug.everyone in my org is facing this issues.Spoke to a friend in another org, they are facing this issue too.Will keep you updated, once I have any resolution from the engineering team.

I agree, I will post here the solution that the support team provides.Wait for it.

May be issue at my end then, I need to raise a ticket with the support team.Thanks @Jennifer_Dungan