Currency fluctuation impact on unbilled services (Webinar Attendee Question)

This question was asked during the Proformative webinar "Convergence of Financial Instruments, Leasing, and Rev Rec Standards."  A video of the webinar can be viewed here: https://www.proformative.com/resources/webinar-video-convergence-financial-instruments-leasing-rev-rec-standards

In our industry, unbilled services are an asset. As exchange rates fluctuate, the value of the asset in the functional currency fluctuates. Once an invoice is presented, we calculate gains and losses on that asset, but there is a difference between the functional value of the unbilled srevices asset at the time it was earned and the value of the receivable. That difference is due to exchange fluctuations. What do I do with that difference? Should it be a realized gain or loss?