Small transactions going back to sender when comming over forwarding address

Small transactions going back to sender when comming over forwarding address

I have set up a Litecoin forwarding address with Blockcypher which sends any incoming funds to a destination address. I generated the destination address by myself, so no one knows the keys. Its working, the destination address receives amounts everytime I send some to the forwarding address. But I can see in the transaction history, that sometimes the destination address sends back very small amounts (I saw 4400 satoshis everytime) to the sending address (the address before the forwarding address) at a higher block-height then the original tx. This small "reverse txs" happen sometimes only 3 times, sometimes 6 or even 8 times after the original tx.. Is this a normal behavior of Bitcoin/Litecoin? Can somebody explain?

Here I uploaded a transaction history: https://pastebin.com/Z1z612ZW

Update: Maybe it has something to do with lightning?

http://bit.ly/2GKrpop