The system is automated so it can be that the first connection he found is not convenient or even not possible. If a human gets his hands dirty generally this will get corrected, it needs either time or a call to customer service who should understand that.
Re-routing via LH would not involve you paying a fare difference, so the price is irrelevant for you. Even if the changes are more than 14 days out, so european regulation does not apply, SK still have to either reroute you or refund you.