Spawn platform in flat world with "The Void" preset don't generate properly.
Affected chunks seems to be corrupted.
I've tried to reproduce that, and issue doesn't reappeared.
Environment
Java 1.8.0_25 64 bits.
3Go RAM allocated.
8x Intel Core i7-2630QM @ 2.00Ghz
Nvidia GeForce GT 540M/PCIe/SSE2
Windows 10 Home 64bits
This issue duplicates MC-89249