EVM430-FR6043: EVM430-FR6043+TIDA-01486 actual voltage on transducers is much lower than ±12V

EVM430-FR6043+TIDA-01486 actual voltage on transducers is much lower than ±12V

The connection between EVM430-FR6043 and TIDA-01486 is as follows:

I tested the voltages on J3 pin2 (yellow) and J4 pin7 (blue) of TIDA-01486 using oscilloscope.

I got different amplitude with or without transducer connected on J4 pin7 and pin8. The voltage can be ±12V, but it goes to only ±4V with the transducer. As shown below:

I tried to change R36 and R38 to smaller ones (for example 100Ω), then the voltage was larger but it started to vibrate as shown below:

I was wondering if you could provide some suggestions to modify the TIDA-01486 circuit so that larger voltage could be supplied to transducers.