I have a project I've been working on for a few years using 10.2 In the past I have been able to update the gdb by importing data from a shapefile to an existing feature class. ArcMap would tell me there was already a feature class with that name and did I want the data to go in that feature class, which I would allow. The result was a feature class with updated data that was still linked to my annotation via a relationship class. Any new data would have annotation generated for it.
When I went to follow the same process in 10.8 ArcMap didn't ask me about the naming conflict but instead imported the data and deleted the relationship classes. Was there a change between 10.2 and 10.8 that would cause this or am I missing something?