left field, can you confirm that the component isn't component controlled out? (unlikely since you can add other bcs to it)
next possibility, is that face touching fluid? if it is touching solid or touching an internal space that is omitted, that BC isn't valid.
The component was not disabled nor was there a problem in regard to the fluid domain. I opened up the simulation this afternoon, performed a rebuild (like usual), and all of a sudden there is no longer a problem with the boundary condition. I can't think of any reason for this. I'm going to just chalk it up to some program quirk.
Thanks for the response though.