My old gym teacher also taught science because we just couldn't find another teacher, and was genuinely surprised to learn there were forms of matter smaller than atoms.
My health teacher was a "permanent substitute" situation where we just watched movies the whole semester and got A's.
One of my math teachers died and we just...never hired a replacement, so nobody learned anything that semester.
Bonus: my driver's education teacher was arrested for a DUI (but not terminated)
These situations were all in different schools in different US states, so the lack of quality control in admin that you describe definitely resonates.
My health teacher was a "permanent substitute" situation where we just watched movies the whole semester and got A's.
One of my math teachers died and we just...never hired a replacement, so nobody learned anything that semester.
Bonus: my driver's education teacher was arrested for a DUI (but not terminated)
These situations were all in different schools in different US states, so the lack of quality control in admin that you describe definitely resonates.