For the first, we're mostly past the point of just "testing". So I don't see that too much anymore. Mostly I still see that though in bug reports generated by AI by someone else. There is usually some underlying bug being reported, but the AI explanation and "helpful suggestion" is typically inaccurate. Generally, suggested fixes are terrible. (They likely work, but fix a symptom not the cause.)
The second still happens, but with much less regularity for me though. It does make mistakes though.
In areas where I'm not as skilled it's very hard to spot errors. When researching general information I'm mostly accepting it on face value.
I find the bug-report thing really interesting. For lots of simple bugs it's great. For more complex things it seems to be very superficial- if a 0 causes an issue here, add a simple guard for 0. There's no depth of understanding why the value is 0 in the first place, when it should be set. If it can (incorrectly) be 0 here, where else might 0 be impacting the code?
This informs my opinion of vibe coded stuff - where there is no skilled human inspection. I expect that code to be of a poor underlying quality. Especially if it's AI changes to an existing human-coded app.