Same for me.
Played a world in 1.5.
Explored a full maximum zoomed map.
Updated server to 1.6.2.
Couldn't find horses.
Then recreated the map with the same seed in single player mode.
Instantly found horses in the first plain biome.
Seems like horses can not spawn in plains genereated before 1.6.
Best Regards
same here.
created a map
made duplicate
put one in frame
after a while, my white pointer didnt move and was fixed at the maps location (over the green point)
after a restart of the server, the issue did not occur again (until now, 5 minutes later)
server: 1.5.1
I have a similar problem.
Started the map in 1.5.
Walked around the whole map at lowest zoom level – all stronghold must have been spawned.
After the update to 1.7 the eyes of ender point in different directions.
I also discovered that the seed now generates a different map than before.
I cannot say since what exact version this happens.
But I took my world from the server and tried it in single player creative mode. Couldnt find a stronghold.
Regenerated the map with the same seed, and found a stronghold immediately.