Auto upgrade is downgrading my base

Sorry, I am playing on US Survival. Also, I just went inside my base, and nearly all of my first two floors had downgraded back to wood. Numerous supports on the upper floors also keep downgrading to wood.

I filled my TC with wood and stone and hit auto-uprade. Occasionally, one material would run out, and I'd add more. Very large base started as 95% thatch (I upgrade some parts to wood), and I allowed auto-upgrade to do most of the work. I supposed you'd have to build a massive base from thatch and occasionally allow one material to run dry, occasionally refilling. If you'd like, you have my permission to test anything you want in my base. It's possible this downgrading would happen again if I put wood in my TC. Feel free to mess around.

Hey, Death.

Colonel Cony just showed me how you can choose the material you want to upgrade to. I had it on wood, I think. I switched it to sheet metal just now and it's working perfectly. I guess by having it set to wood, was the thing downgrading my base. You can wreck my base. lol I don't give a crap.