Yeah, those pins that are working out need to have lock tite and then put heat shrink over the joint. All CVD's need this done. It is not exclusive to Losi. Any vehicle could lose the cross pin at anytime. Even after 3 min. of runtime. So take the front and rear center drive shafts out and build them with lock tite on the set screws and wrap with heat shrink. You should be solid after that.
Also with all 8th scale buggy and truggy check the clutch bearings often. These bearings take a lot of heat and abuse. this also lets you inspect your clutch shoes and springs as well as your clutch bell. Good idea to check these about every 45 minutes to an hour of runtime. It will save head ache down the road.