I'm stumped.
I was trying to replicate a file (corporate wallpaper) to branch offices via SYSVOL (so that workstations in branch offices don't have to pull the file from HO). However, the replication only worked for some RODCs, but failed on other RODCs.
On one failed RODC, I tried forcing replication by using the command ntfrsutl.exe forcerepl DEST_RODC_NAME /r "Domain System Volume (SYSVOL share)" /p dc01.example.com
... and within minutes, the wallpaper appeared!
What could possibly the problem here? Why won't some RODC perform automatic sync?