Movie vendors, however, preferred yellow corn, which expanded more when it popped (creating more volume for less product) and had a yellowish tint that belied a coating of butter.
Now, it’s unusual for people to use words to mean their exact opposite, and I have a vague idea that I’ve seen this usage before — belie meaning not “contradict” or “conceal”, but more something like “dishonestly suggest”. If this is a trend in the word, it’s a fascinating slippage, because this inversion of the meaning — from concealing something true to proclaiming something that is false — is a bit of a double negation. In both cases, the subject is dishonest. In the usual sense of belie the object belied is true. In this new meaning — or maybe it’s just a thinko — the thing belied is false.
Interestingly, among the meanings included in the OED are single negations of what I consider the central meaning: Straightforwardly claiming (or demonstrating) something to be false, as in this 1893 citation from the Journal of the Royal Statistical Society:
The postulate of free will and moral responsibility assumed by the classical school is belied by physio-psychology.