Hmmm. I had this exact same thing just happen to me right now.
This is where the build table stopped for the fill reference.
Not a particularly tall print, only 1086 layers. Prior print this am (950 layers) didn't have this problem (although I DID have a print failure; first in several months - 4 duplicate rings all failed when 3/4 printed)
I manually lowered the build table to fill the vat with Emerald, but I'd sure like to know what happened. Too big a coincidence that this happened to me and the Original Poster at the same time frame.