I'm not sure this counts as a bug, and I may have just been supremely unlucky, but the mushroom nodes for glowshrooms/deathshrooms did not appear until, at 90% complete, I left and re-entered the Lost Grove. After that, they started spawning a-plenty. I think the spawns may have just... not been loading, because I hadn't left the Lost Grove after getting to that stage?

Since you left and re-entered (respawned all of your nodes), I won't be able to look at the database to see what was going on. My best guess would be that maybe through previous zone exits, you increased the respawn delay to a long time? I think it can go up to like +24 hours with extreme exiting and re-entering.

If it happens again and you don't mind waiting, let me know and I can take a look at the database to see exactly what the issue is - whether they're broken or delayed and then try to figure out the why.