AI Impacts has a list of reasons people give for why current methods won’t lead to human-level AI. With sources. It’s not exactly what you are looking for, but it’s close, because most of these could be inverted and used as warning signs for AGI, e.g. “Current methods can’t build good, explanatory causal models” becomes “When we have AI which can build good, explanatory causal models, that’s a warning sign.”
AI Impacts has a list of reasons people give for why current methods won’t lead to human-level AI. With sources. It’s not exactly what you are looking for, but it’s close, because most of these could be inverted and used as warning signs for AGI, e.g. “Current methods can’t build good, explanatory causal models” becomes “When we have AI which can build good, explanatory causal models, that’s a warning sign.”