I'm using NCS 1.4.0 and 2 boards nRF5340PDK.
I'm using central_uart and peripheral_uart samples. Both display when connection interval change.
The central_uart use BT_LE_CONN_PARAM(6, 12, 0, 400). The peripheral_uart use default value that are:
#define CONFIG_BT_PERIPHERAL_PREF_MIN_INT 24
#define CONFIG_BT_PERIPHERAL_PREF_MAX_INT 40
When I test the samples, the connection interval is first correctly set at 12 but after 5s it change to 40. Here are the logs:
