Has anyone seen this before?

Don

All the time, before we got the Sentricon system. I still have residual
damage, but I'm winning. They seem to like drywall paper, probably a
desert after gnawing a 2X4. That system is pricey, I paid $1700, + 300
annual fee, but it beat the bugs, now we just have to clean up the
mess. BTW the house had been inspected and treated yearly for about 5
years before I bought it, but it never really eliminated them, it just
kept them in check.

http://www.dowagro.com/sentricon/us/