Salem

Well I was building mine entrance in parts, last few boards make percentage counter go nuts and over-clock it above 100%.
Its either bug in calculating % of the building done or my char has some Russian ancestor and is working at 110% of his power.

It's not a bad calculation. It's another bug and I don't think anyone has been able to reliably reproduce it. Best guess I've seen is that a decay tick destroys materials that were already in the sign. Did you have to add more than you thought you had already put in?

Yes I was sure that I put all materials except nails, but it seems that 10 board vanished.