It is a long resolved issue by now I've learned, teething problems so to speak. With our brand new equipment
we now operate to HRG which takes us from Hellas FIR to Sofia FIR via EVIVI indeed. Caused at first by less than optimal FPL addressing on behalf of HRG ARO and paperwork troubles with Sofia.
Just recently I've sat on the sector next to some 15k+ hrs broken English speaker who said he had to reroute via Skopje before.
Anyhow what thanks to PPRuNE and HD for thoughs from the other side (generally speaking). Yet I imagine the real seat of pain is under the canopy of intercepting aircraft.
Cheers,
FD.