Since I update to v0.9.6.11-eaf7af2 I am seeing the same thing for all the blocks.

getmininginfo
{
"blocks" : 538434,
"currentblocksize" : 0,
"currentblocktx" : 0,
"difficulty" : 0.00000135,
"errors" : "This is a HARDFORK build for block 555555",
"genproclimit" : -1,
"networkhashps" : 3302921396,
"pooledtx" : 1,
"chain" : "main",
"generate" : false
}