Custom Routes behaving differently in testing and in actual races

I’ve created a few custom routes that work fine when I test them, no visible flaws or missed checkpoint warnings. BUT, when I try to use them in races (solo/pvp/coop) I’ve noticed most of them suddenly show missed checkpoint warnings, some I can speed through just barely, others I get stuck in a infinite reset loop. One would assume when you test your custom routes, you’d get the same warnings. Is this a glitch or is there some obscure thing I’ve missed? Either way, it’s alot of frustration and time constantly having to rethink a route to somehow fix this. Any and all helpful advice/help is welcome.