What is the DelimiterByte in Bluetooth?
What clock interval do you use?
To test, receive the data as text, set a slower Arduino delay, delay(1000).
Check in this Community topics about Bluetooth.
Edit: Here is an example with a small Stepper Motor, in this case information is sent from the App to the Arduino.
Bluetooth HC-06. Arduino. Send. Receive. Send text file. Multitouch. Image - #14 by Juan_Antonio