Customs Creation: Chart Falls Out Of Sync In-Game But Is Fine in EOF

Recently I downloaded a newer version of EOF and the new DLC builder. The charts I've made since then, I notice they seem to fall further out of sync as the song goes on. It usually only equates to about half a beat off, but still annoying. No matter which chart I check, in EOF they are all perfectly well synced. Has anyone else encountered this problem?

I used EOF 1.8 RC12,