I've created another public KEY, this time I didn't even look at the prive key.
i've created on the wallet that I'm developing using NBitcoin library.
I'm compiling everything from source code
The public address is "mwT5PqSoLCeojDhghhBdXFCMMwGYxb34Ge"
Did you check the private key to see if it is actually created randomly (convert to hex, it makes it easier to see)?
Maybe the code you wrote has some flaw in it when it calls the RNG and creates a non-random key which some bot is already watching to steal its funds right away.