Okay, here's video proof of the bug:

The bug isn't the bug I thought it was however; the boost did apply for the full hour which ended between the first and second run. The display timer for the boost on the main screen appears to be slow and showing 3 extra minutes that I shouldn't have had (even though the multiplier still shows up at the end of the second mission, the amount isn't multiplied at all).

For what it's worth, this hour test resulted in 40 total runs that were boosted with an average (boosted) gain of 42873g/run.