This "Senior" or parent transactions has "Unknown" TXID and built in a weird way.
[Input 1, Input 2 ---> Outputs: Gambling Site Address, Change of Input 1, Change of Input 1 to the same address, Input 2]

I think you're misunderstanding "Inputs" from "Addresses".
An Address is just an identifier and can have multiple "Inputs" or UTXO, so, if the Marked Red one have received bitcoins before, there's a chance that the second transaction's input wasn't spent from that (screenshot) transaction and it's a local transaction (No TXID).

Are you sure that there's no Local transaction in your history? Small Icons on the left should be green check or Gears for unconfirmed Tx.