Thanks! I'm glad you liked it, even in the prototype stage. Yeah, it's a known bug (one of many on my loooong fix list). As a temporary workaround, try deleting the save files at:
C:\Users\[USERNAME]\AppData\Local\UnrealBoxing\Saved\SaveGames
This should reset your customization options. I'm working on a proper fix for the next update.
Thanks for reporting this.