Loss of control and warnings after power cycling

Trying to figure out what may have caused a series of faults ending up contributing to a crash. Background: We have been testing a sense and avoid system utilizing the TX board along with optical sensor. Haven’t had any issues until recently. Sense and avoid is from a third party so not sure if they introduced something or if it is something related to pixhawk/firmware. We can consistently recreate the error with the following procedure. Fly, activate sense and avoid, land, power cycle, get bad gyro health warning along with strange changing of altitude display on MP. Also just before everything goes haywire, we get a clank similar loss of synch on startup - but esc log doesn’t show much other than prop strike - but weird for sure. The first time this happened we tried flying even after the strange prop/motor slap and had no control in stabilized as soon as we took off. Haven’t done that again! I have attached the log if anyone is willing to take a peak and provide some thoughts??? Thanks.[https://drive.google.com/a/uavamerica.com/file/d/0B1W3CJgEHi-GR2pjMDIxMHJXUFk/view?usp=sharing]