Hello,
I have experienced some softdevice hardfault in my multiprotocol application. I use https://github.com/NordicSemiconductor/nRF-IEEE-802.15.4-radio-driver/wiki with the raal softdevice arbiter.
The problem is most likely due to an inaccurate configuration of the clock. I have done a workaround to fix the problem by changing the default nrf_raal_softdevice_cfg_t config of the nrf_802154 library.
By default, NRF_RAAL_TIMESLOT_DEFAULT_SAFE_MARGIN_US is set to 3. Changing it to 20 makes the application working better, but there is obviously a problem somewhere.