I think he is saying the wallet is open source because it's an error from the developer and if it was open source, it will be easier for other develop to detect the bug and release a latest update of Trust wallet and patch up the bug, you can see that the OP has said that he reach out to Trust wallet support and he was told that the double transaction was a bug, it wasn't a dust TX as he indicated from beginning.
The next way to avoid this reoccurrence type of problem is to make sure that your wallet is open source so that when this happens, you will get I tail quickly from other people that used similar type of wallet and then you can also download the latest update. Since OP is using Bitcoin for transaction, I recommend wallet like Electrum wallet, there is an pc version and mobile version and he can check Blue wallet as well.