Why is FX movement booked as Unearned Revenue?

I am working on a Project Billing implementation, learning as I go. I've been doing some testing with currencies.

My functional currency is SEK, and I have a project with a currency of EUR, using a rate schedule with EUR. When I run the Generate Draft Revenue process, it books an entry equivalent to the EUR amount for the exchange rate defined as of the last day of the period (in Production, this will be the Corporate rate). This is what I expected.

When I ran the Generate Draft Invoice process with a different date, it used the Spot Sell exchange rate (the rate I specified) for the invoice date. Also what I expected. However my journal entries for the transaction are as follows: