Does the trace look any different if you arrange your code like this
SPI.beginTransaction(SPISettings(2000000, MSBFIRST, SPI_MODE1));
digitalWrite(slaveSelectPin, LOW); // take the SS pin low to select the chip:
stat = SPI.transfer(0x00)...
I think you should change:
if (channel == MIDIchannel
&& control == servo1)
value = map(value, 0, 127, 0, 179);
value = pos1;
myservo.write(pos1); // sets the servo position according to the scaled value...