iOS 18.6.2 is not merging my iPhone calls

iPhone 13, IOS 18.6.2. When I call someone and then try to add another caller, and I attempt to merge the calls, the first caller is dropped. This has been a recurring issue that was resolved in the release before 18.6.2, but has now resurfaced.

[Re-Titled by Moderator]

Original Title: IOS 18.6.2 not merging calls