I just had a chunk reset also. At first I thought it was due to an out of date mod, but I upgraded all last weekend and it happened again.
Currently have loaded
MC1.6.4
Forge 9.11.1.965,
AE r14.finale3,
IChunUtil 2.2.0,
IC2 2.0.370,
TC4-4.05b,
Forestry 2.3.1.0-698
Highlands 2.1.4...