Opportunity Team - Default Currency on Opportunity Team Split Revenue

Hello,

I want to know the default currency on Opportunity Team Split Revenue field when the new team member is added to opportunity. Does it take the currency from Opportunity or it takes the default currency of the user who is being added to team or the default currency of the user who is adding the team member?

I have seen 2 different scenarios till date and I want to know the exact behavior.

-> For one of the Opportunity in our CRM, the Split revenue was carried from the user's default currency who added the team member and not the Opportunity currency.