We all mess up our nav from time to time, no matter how long we've done it - even Bob. It happens a lot more in the first few years, especially to strong athletes who can run faster than they can navigate.
My best nav education has come from my biggest mistakes. It has also come from identifying and reinforcing the things I did well in a race - something a good coach taught me to do, since we tend to focus on our nav errors.
Keep at it, review the map with Bob post-race, explain what you were thinking at certain points, and get him to tell you what he was thinking and make suggestions for you. Do some map training at a hiking pace and only run when you're 100% sure where you're going next. You have incredible raw talent and love for this crazy sport that will keep you learning for a lifetime. You'll be kicking everyone's butt eventually!
I think the challenge of it is what makes me enjoy it so much and I guess it's to be expected since I don't practice! Much like a lot of things, we are reluctant to work on what we aren't good at.
Either way, I will continue to read maps (we have an excess laying around!!) and have fun getting lost...while trying not to get lost! ;)
For me, it is skate skiing that I am reluctant to work on so I totally get it. :)