Does "any" change to "some" in reported speech?

Question

This sentence appeared in a reported speech exercise assigned to me.

"Are there any oranges in the fridge?", she asked her mom.

This is the exercise's key — it changed "any" to "some" when the above sentence is changed into reported speech:

She asked her mom if there were some oranges in the fridge.

Is this correct? I have never heard of the changing "any" to "some" rule when learning about reported speeches before, nor have I ever heard it when listening to British and American speakers. I feel like it's way more natural to say:

She asked her mom if there were any oranges in the fridge.

Is preserving "any" when changing to reported speech grammatical? I couldn't find any reliable information in dictionaries and other forums. Any and all help is greatly appreciated! Thanks in advance!

Answer 1

There is no need to change "any" to "some" and your version with "any" is correct.

It is grammatically correct to say "are there some oranges" and the meaning is almost the same (perhaps there is a difference if there is only one). The question with "any" is more common, but "some" is also used, especially when asking for an uncountable noun:

Do you have some paper? Do you want some rice?

When reporting speech you need to preserve the meaning, and not the phrasing. So a native speaker might change any to some, but it's not required.

_{Also, who keeps oranges in the fridge?}