rtapi_app: caught signal 8 - dumping core

Brand new setup using stepconf.   if I spin the spindle encoder quickly by hand I get: rtapi_app: caught signal 8 - dumping core


Even if the machine is still in e-stop.   Simple config using stepconf   LINUXCNC - 2.9.0~pre0


All default settings other than manual edit of LPT base address and changed   setp encoder.0.position-scale 4000.000000    Default is like 100 vs 4000


Any ideas what causes this error?  


The only mention of a similar error: forum.linuxcnc.org/24-hal-components/358...hercat-lcec?start=10

Someone tested on LCNC 2.8 and there is no error.