Tiny ceramic bypass caps are weird

[Paul Perry (Frostwave)]

how weird?
http://www.avx.com/docs/Catalogs/cdesc.pdf
shows that their capacitance can change by 50% just from having a few DC volts across them
Thanks to Tim Stinchcombe from synth-DIY for pointing out this link

[Gus]

Depends on the type of ceramic cap.  Also this well know the sencore lc102 make note of dielectric stress with voltage there is a different setup for testing for ceramics on a LC102.

Look for the C. Bateman articles on caps you can find on the web some real good stuff in there.

[Sir H C]

And some will "sing" the note if it is a charge pump or other oscillator.  Can be really annoying.