You exposed the beige undercoat paint.

Strié is a glaze done OVER a base paint. If done in browns over beige it's sort of faux wood grain.

The grain-coat was a colored shellac. Not unheard-of, more typical to have used a distemper paint for the graining, then topcoat with clear or amber shellac.
I tried graining with colored shellac once about 20 years ago, it requires one to work really fast, as the shellac sets in well under a minute. I have since learned of shellac _retarder_, which perhaps is key.You add butyl alcohol to the shellac to retard it, BTW.
Casey

Thanks, this makes perfect sense. I assume I am better off not trying to remove the distemper?