Gameplay - Custom timed races reset to 5 minutes long (1792041)

Bug Info: Using game type Custom with the end condition set to time, the race timer will automatically reset to 5 minutes after closing the event settings menu.
Platform: PC
Edition: Gamepass with Premium add-ons
Account: Solo
Attempted fixes: Game reboot, lobby reboot, multiple different race hosts
Content Update: Not happening prior to Update 8

As seen in this video, the race timer automatically resets to 5 minutes when using Custom game type, regardless of whether or not I input a custom amount of time, or use one of the preset lengths. This only occurs to Custom game type and does not affect Timed Race game type.