Tested on r6646 pak64
Sorry this is a known issue.
North and west edge of rotated save map will be broken after reloading it.
How to reproduce:
1. Load the attached savegame.
2. Rotate twice (180 degree).
3. Save this map and reload it.
Result:
North and west edge are broken.
Thanks for the report.
Can reproduce simply by creating a new map, saving, loading, rotating twice, saving and reloading. Also occurs with loading any map seemingly, rotating twice, saving and reloading.
Also can confirm that this has error occurs with r6650 and has been present since at least r6600.
Will look into this later.
Edit: Strongly suspect this has been present since map edge no longer have to be at sea level, and that map save load assumes grid at max width/height will be at sea level. Fix should be relatively easy after work...
Fixed in SVN 6651. Issue was with loading not restoring grid for south and east edges of map. New code added to restore these grid heights. Not only that but there was a piece of code elsewhere which then forced these to sea level which I then had to remove...