Yea, capacitors do some very strange things.

for example, I had a capacitor that read pretty darn good in ESR, and the capacitance was still within its 10% tolerance its rated for, but still be bad. it was part of a filter circuit and the ESR needed to be about an ohm or two less than what it was.

just that minute of a difference caused the circuit to totally not operate. (in case you were wondering, it was the SMPS of an old zenith projection tv).

I had to do a double and triple-take on that capacitor. Replaced it anyway, and the power supply came right on.