Nextion Display Causes NAK from the MMDVM, command = 0x80, reason = 1 with v1.6.0

[robrobinette]

I have a Nextion display connected to the modem. It is fully functional when using v1.5.2 firmware. When running v1.6.0 on an hs_dual_hat I have turned the Nextion display on and off in the pi-star configuration page and every time I turn it on I get the same NAK errors (endless stream):
W: 2022-08-09 18:26:09.868 Received a NAK from the MMDVM, command = 0x80, reason = 1
W: 2022-08-09 18:26:10.270 Received a NAK from the MMDVM, command = 0x80, reason = 1
W: 2022-08-09 18:26:10.270 Received a NAK from the MMDVM, command = 0x80, reason = 1

M17 mode stops working and the pi-star dashboard "M17 Network" shows "disconnected" but the pi-star dashboard shows M17 mode enabled and network status in green. I get the NAK messages even when M17 mode is disabled but all modes are still functional. When I turn the display off in the pi-star config page the NAK errors stop and M17 functions again. I am unable to run the Nextion display with M17 mode enabled.

This is my MMDVM_HS build Config.h:
#define CONFIG_H
#define MMDVM_HS_DUAL_HAT_REV10 (or MMDVM_HS_HAT)
#define ENABLE_ADF7021
#define DUPLEX (comment out for simplex modem)
#define ADF7021_14_7456
#define AD7021_GAIN_AUTO
#define STM32_USART1_HOST
#define I@C_ADDR 0x22
#define ENABLE_DEBUG