kas:
not normal behavior
Possibly electric noise or MCU internal timers interaction
please post your full code, I will try it on my side
You wrote here that Softserial doen'nt work with servo lib. It is always true?
What happens if you comment
sendBlueToothData();
The problem is less visible but ticking is always here 
(and data 3 is not updated on Android screen of course)
Let me know
Here is my starting skech I use attached.
JBC1.ino (9.63 KB)