You'll still end up with two separate UTXOs, they won't be merged only because they were sent to the same addresses. They come from different sources.

Think of it like putting two literal coins into the same wallet. They're there together but they're still separate coins. When sending two or more coins as part of the same transaction, you're effectively melting the pieces you're sending and a new coin is created in the destination address. If you send another coin to that same address, again you end up with two coins.

Hope this helps!