Ahhhhh this brings back memories... not sure why that thread feel off my notifications list? I never noticed that the OP had made the final reply??!? Apologies for that.

Right, I have to ask the obvious question then... Given that you were copying both LTC and BTC addresses... I assume you checked the LTC "sign message" list for what you believe is the BTC address?

Or used the iancoleman.io tool and set the coin to LTC with your seed and checked those addresses for what you think is the BTC address?