Sounds like a bug. You might want to report this on the project bugtracker: https://github.com/acidanthera/bugtracker/issuesWith the driver and with ExFat dives connected, stuck before the bootpicker.
You will most likely be asked for a debug log. You can generate one by setting the "target" key in your config file to 65 and restarting after temporarily swapping your BOOTx64.efi, OpenCore.efi, Bootstrap.efi and OpenRuntime.efi files for debug versions.