Stack Exchange has decided to raise question upvote from +5 to +10 and applied it to all communities, including the private ones. I image that this one implemented like this because it was much quicker (no customization at community level).
I have raised the concern about the private communities being affected by this change and it is scheduled to allow some sort of customization for this sometime in 2020.
If this becomes an option, should we use the opportunity to come back to +5 value for the question upvote?
Personally, I am in favor of +5 instead of +10 because it is significantly harder to provide an answer that asking a question.