This is an excellent example of the way IQ tests can indeed succumb to cultural training effects. It's pretty clear that this is what's going on with the Flynn Effect, for instance, which is not a real increase in intelligence since not g-loaded:
http://psychology.uwo.ca/faculty/rushtonpdfs/2010%20Editoria...
It's also why Raven's matrices don't work as well as they used to (IMHO). I think my own childhood IQ score is 10-20 points too high, because I'd seen too many IQ-test-like problems.
So, certainly a problem with all IQ tests. But a minor problem, or an existential major one? If it was a major one, these tests would lose their predictive validity - which remains quite high.