"The glass, is there water in it?"
Translation:הכוס, יש בה מים?
The grammatical gender of כוס has some fluctuation in the history of the Hebrew language, so it makes sense that it might cause some confusion today in Israeli Hebrew. In classical Hebrew, כוס is feminine but in rabbinic Hebrew it got treated as masculine for the purpose of agreement with adjectives, e.g., כוס ראשון (Pes 10.2). Source: Pérez Fernández, Intro Grammar of Rabbinic Hebrew, 6. People think that Aramaic had an influence on this change of gender because כס in Aramaic (Jewish Palestinian Aramaic, כסא and כוסא Jewish Babylonian Aramaic) was masculine. On the word in Aramaic, see the Comprehensive Aramaic Lexicon online at http://cal.huc.edu/ There's an important book on this topic: Malka Mushnik, The Gender Challenge of Hebrew (Brill, 2015). On p. 64 the author states that the preferred gender for nouns in MH is fem.
As a native speaker, I am not shocked by this - perhaps bcs I also speak French where this would be a common colloquial usage. But I could certainly imagine myself pointing to a glass and asking if there is water in it by saying "That glass - is there water in it?' What do other native speakers think?