I think it's more likely a problem that the GP poorly worded their initial statement, rather than actually moving the goalposts. They were probably having trouble with a few thorny bugs, tried ChatGPT, got nowhere, and forgot to qualify their initial statement with "for the few non-trivial bugs I tried".

From the external point of view, the goalposts moved, but from within the GP's poorly expressed mental model, they haven't moved. But, that's just a guess.