I have noted there is a bug in FBB where it usually does not allow for multi-year veteran minimum contracts when the raises year-to-year exceed 10% (which is pretty much all contracts except those for players with 10+ years of service since the vet minimum is flat after that). Occasionally I can "trick" the system into accepting them but usually I can't.
Therefore, going forward, to make sure no contract gets tossed out due to bugs with the sim engine, free agent contracts for the veteran minimum will be restricted to a single year in length (i.e., no more multi-year veteran minimum deals).