btw - I was also seeing this same behavior (and same register dump that @chrisgr99 got). I’m on a NRF52840-DK with the Adafruit BSP. The failure seems to only occur if I try to ‘step-over’ the startup of the freertos scheduler (vTaskStartScheduler call in main.cpp of the adafruit arduino env).
If I don’t do that (and instead just let it run) everything seems to work okay and I can set breakpoints nicely in my app.