So I've tried my hand at making some covers, and the problem is, I've found that around half of the USTs I use just don't work? I'll do everything like use the plugin of romaji to hiragana so the UTAU can read it, and fit the UST to the UTAU by doing all the region property settings and whatnot - and even tried to use other UTAU which then also stay silent during specific USTs. TL;DR - only certain USTs will result in none of my UTAU making any sound from them at all. Others are fine, but it seems like a hit or miss, knowing if they will sing a specific UST or not. I'm confused and wondering if anyone else is experiencing this and can offer guidance.