I don't think it's a bug. See "Horseshoes" message string from 5Apr09. I scaled map screen A-H left to right and 1-8 top to bottom. Area B2 can have 2 HS in following seven zones; NS crater, IF tavern, BS stable, DS road, HI, PV Hydras, SW in front of Hive entrance. Area E2 has HS in nine zones. Area D4 has HS in seven zones.
If anyone wants, I have a sav file w/ 4 level 1 Sorcerers standing outside Hive entrance w/ 2 HS on ground, surrounded by many Devils on 13Jan. The position can be survived and you'll have to figure out how to escape. Four SW HS have been picked w/ 2HS within reach.
Also, in nine zones between NS and SW there are 44 non-stable HS laying on ground that will still be there when reentered.
If anyone wants, I can email file or perhaps someone can host the file.