The addition of multiple channels, on different chains, using the same identifiers between two nodes creates an ambiguity where the funds would be transferred. This situation can arise when there is a route A -> B => C, where => indicates two channels, one in litecoin and one in bitcoin, and both channels use the same identity for C. In this case, the instruction to forward 0.01 units to C is ambiguous, as it could be denominated in either litecoin or bitcoin.Although this situation is not dangerous, it results in guesswork. If A transfers litecoin to B, then B will not forward a higher value to C using bitcoin, and if it were bitcoin, then the final recipient would not sign off an inferior amount than what he expected. However, in a worse case scenario where C is a charity accepting donations, A's software screwing up and not realizing that C was litecoin instead of bitcoin could result in B collecting a huge fee, while C gets a tiny donation.