1. As an example you are looking at a non-synced repeating event in the agenda view of the Business Calendar 2
2. Hide the pop-up window and hit the menu button on your device (here at the top right corner)
3. Choose → Sync now in the menu and the Business Calendar will force the Android OS to start the synchronization with the Google-servers (note to make sure, that your internet connection is working properly)
Hint: Depending on your amount of events it may take a few seconds or minutes to finish this process.
4. Try to delete or edit the same event again and you will notice the additional 'Only this event' option
Please remember, that it works for local calendars (which have been created within the Business Calendar 2), too. It will, however, not apply to any other local calendar i.e. a local calendar, which wasn't created in BC.
*** On devices with custom Androids (eg. Huawei, Xiaomi etc.) the system doesn't allow the proper functioning of the function. We managed to find a workaround for the series on those devices, but it works only for the event series created directly in BC. Any other series (created in other calendar app/ synced) will be still affected by this system limitation.