I've found that a few of the Scandi and European makers, especially Elme, produced cased glass with very weak white interiors. I've even got a couple of pieces from HG's Carnaby range with less-than-white insides.
Saying that, I'm not doubting the possibility that this vase may be Chinese - it seems to lack the wackiness of a most cheap 'n' cheerful Scandi cased glass of the 1960s/70s.