The circuit is basically driving the "bus" single ended, because the negative line is clamped to the circuit ground. So I wonder where you expect differential signals, that are 180° out of phase.
At the driver side, Q2 emitter and collector voltage can be expected out of phase, but this property doesn't matter for the circuit operation, I think.
Referring to the said 110° phase difference. You didn't tell, how you measured it and for which frequency it is achieved.