Maybe "it feels weird" is all they can do on their own, but they need - for want of a better term - a debugger for more detailed analysis. A bit like how we could say "it feels weird" but may need further testing with "human debuggers" (blood tests; EEG; X-ray; lung function test, though what you might need all four of those for at once I dread to think) for a better result.
AIs might have simple tests built in. Current computers have POST, and to quote the late, great Terry Pratchett: "Most people, on waking up, accelerate through a quick panicky pre-consciousness check-up: who am I, where am I, who is he/she, good god, why am I cuddling a policeman's helmet, what happened last night?", but any further diagnostic tools may not be commonly necessary, so they aren't part of common chassis because it's extra expense and extra things to go wrong.
Also, I'm not sure the Thumblord Incident is a reliable indicator of how AIs work. It was a funny set of strips, and may have been true at the time, but Jeph has made AIs and their functions a lot more realistic since then.