Enabling CONFIG_USE_SWITCH=y causes usage fault on nRF54L15 with nRF Connect SDK v3.4.0-rc1.
Where it crashes: Context switch on interrupt exit, Zephyr arm-m-switch.c: arm_m_exc_exit() → arm_m_must_switch() → arm_m_do_switch() → arm_m_cpu_to_switch() / fpu_cs_copy() (~line 367).
SDK: nRF Connect SDK v3.4.0-rc1
Config: CONFIG_USE_SWITCH=y, CONFIG_FPU=y, CONFIG_FPU_SHARING=y, CONFIG_BUILTIN_STACK_GUARD=y, hard-float ABI.