GIB programming flaw

I was playing money bridge while eating lunch today. My robot had:
AKQJ, AKxxx, T, AKQ. It opens 2C, I bid 2H, which it said showed 5+
hearts and 8+ points. It bid 4NT, rkc for hearts. I bid 5D, 1 or 4.
GIB passes and I luckily go down only 1 because I was 5-5 in the reds
w HQ and DA and DJ. Needless to say, there were 13 top tricks in
hearts or nt. Cost me $23.20.