That's because you don't understand the tool you are using and use tech-sounding language in the wrong context to look like you do.

GPT models generate text based on the patterns of the tokens it learned during training. The URL it gives you doesn't work because they have to only look legit. It's all statistical patterns.

It's not because they fed it garbage during the semi-supervised training, it's because that literally is what the tool is meant for. Use the right tool like google scholar if what you need are sources.