CONF_DONE goes low after INIT_DONE goes high

I have a very simple one-device Stratix IV design and problem.

An external fpga programs the Stratix IV device using FPP/compression. The whole config file loads into the Stratix IV device, CONF_DONE goes high, INIT_DONE goes high. Everything functions as expected. But then, 2usec later, CONF_DONE goes LOW !! (nSTATUS did not change, and INIT_DONE stays high).

Factory told me "That is strange, that shouldn't happen."

Yep. I know that shouldn't happen. :-(

Anyone ever seen that behavior before?

thanks for any reply.