Hi Jose!
This is a known issue with the Android Pie update from Samsung (see also Auto unlock problem with Android Pie) due to some heavy restrictions on Bluetooth usage in certain modes.
We are working actively on a solution and you can really help us by sending log-files from your App (as described in the topic linked above).
I have a S8+ myself we use for testing and we will keep you updated as soon as we have any progress which you could beta-test (if you are interested).