After Most Recent Update Contact Center Cannot Merge Calls

Our business uses contact center for our intake calls. Part of our intake process requires merging calls so that one operator, the client on the phone, and a manager can be merged into the call. This used to be an option with a merge call button. Now there is only an add call button where the only options are to warm/cold transfer instead of merging the call. Has anyone found a setting or work around for this?