omega2 fails even when stereochemistry is specified

I have a compound with four chiral carbons and one invertible nitrogen defined by a smiles string. All of the carbons have defined stereochemistry in the smiles string. I have run it through 1) flipper and then omega2 and 2) omega2 using the "-flipper true" option, but omega2 fails with "unspecified stereochemistry with strict stereo enabled". I have also tried using the "-enumNitrogen" flag with no change. Am I missing something?