This is caused by the way IFS creates its own signal handler. To enable Cray ATP set:
export DR_HOOK_IGNORE_SIGNALS=-1
in the job script to completely disable any signal trapping by DrHook.
This issue has been fixed in OpenIFS releases 38r1v05 and beyond. For previous releases, either use the fix above or contact openifs-support@ecmwf.int for assistance.