I deleted my chain and peer dbs, then redownloaded the chain on 0.4.27:
Machine 1 (0.4.27):
--- in sync with p2p network
(wallet closed) >>> info
{
  "blockchain_head_block_num": 1283018,
  "blockchain_head_block_age": "13 hours old",
  "blockchain_head_block_timestamp": "2014-12-17T06:27:10",
  "blockchain_average_delegate_participation": "2.18 %",
  "blockchain_confirmation_requirement": 1,
  "blockchain_share_supply": "2,498,420,479.09030 BTS",
  "blockchain_blocks_left_in_round": 86,
  "blockchain_next_round_time": "at least 14 minutes in the future",
  "blockchain_next_round_timestamp": "2014-12-17T19:14:50",
  "blockchain_random_seed": "9c8436243078d56f4ca9216c8233a7758d084452",
  "client_data_dir": "/home/showard/.BitShares",
  "client_version": "v0.4.27",
  "network_num_connections": 8,
  "network_num_connections_max": 200,
  "network_chain_downloader_running": false,
  "network_chain_downloader_blocks_remaining": null,
  "ntp_time": "2014-12-17T19:00:32",
  "ntp_time_error": 0.0020690000000000001,
  "wallet_open": false,
  "wallet_unlocked": null,
  "wallet_unlocked_until": null,
  "wallet_unlocked_until_timestamp": null,
  "wallet_last_scanned_block_timestamp": null,
  "wallet_scan_progress": null,
  "wallet_block_production_enabled": null,
  "wallet_next_block_production_time": null,
  "wallet_next_block_production_timestamp": null
(wallet closed) >> blockchain_list_forks 
   FORKED BLOCK              FORKING BLOCK ID              SIGNING DELEGATE      TXN COUNT      SIZE           TIMESTAMP   LATENCY   VALID    IN CURRENT CHAIN
--------------------------------------------------------------------------------------------------------------------------------------------------------------
        1283018
     11afe1649155b854b5bb3c69021a39151df5ef12          bm.payroll.riverhead              4      1572 2014-12-17T06:27:20     45172      NO                  NO
     ec9e8670a9099bb830fe1275298ca03b1b10c555                         emski              2       998 2014-12-17T06:27:40     45153      NO                  NO
REASONS FOR INVALID BLOCKS
11afe1649155b854b5bb3c69021a39151df5ef12: 30007 duplicate_transaction: duplicate transaction
    {"trx_id":"0b37cd2a4dc1c10ae1ecb7bb44b0af30aaf778b6"}
    th_a  transaction_evaluation_state.cpp:212 evaluate
    {"trx":{"expiration":"2014-12-17T07:34:30","delegate_slate_id":null,"operations":[{"type":"update_feed_op_type","data":{"feed":{"feed_id":4,"delegate_id":14872},"value":{"ratio":"0.045095236539076448","quote_asset_id":4,"base_asset_id":0}}},{"type":"update_feed_op_type","data":{"feed":{"feed_id":14,"delegate_id":14872},"value":{"ratio":"0.00922438485977705","quote_asset_id":14,"base_asset_id":0}}},{"type":"update_feed_op_type","data":{"feed":{"feed_id":7,"delegate_id":14872},"value":{"ratio":"0.000124300399590475","quote_asset_id":7,"base_asset_id":0}}},{"type":"update_feed_op_type","data":{"feed":{"feed_id":22,"delegate_id":14872},"value":{"ratio":"0.001489678120825724","quote_asset_id":22,"base_asset_id":0}}},{"type":"withdraw_pay_op_type","data":{"amount":50000,"account_id":14872}}],"signatures":["1f3b48e355cd4086284045565a299fe46e514cdbe69e2b2147b5f16ea3f22fa8ab4832a7bd4d28527f202a0a8fcb47578d8deaeb8bf769955b0bdcd4a504d07214"]}}
    th_a  transaction_evaluation_state.cpp:244 evaluate
    {"trx_num":0}
    th_a  chain_database.cpp:729 apply_transactions
ec9e8670a9099bb830fe1275298ca03b1b10c555: 30007 duplicate_transaction: duplicate transaction
    {"trx_id":"9273cbde64d4edde9103776c723cf59665af4f71"}
    th_a  transaction_evaluation_state.cpp:212 evaluate
    {"trx":{"expiration":"2014-12-17T07:34:43","delegate_slate_id":null,"operations":[{"type":"update_feed_op_type","data":{"feed":{"feed_id":4,"delegate_id":18766},"value":{"ratio":"0.045084141539375624","quote_asset_id":4,"base_asset_id":0}}},{"type":"update_feed_op_type","data":{"feed":{"feed_id":14,"delegate_id":18766},"value":{"ratio":"0.00922686315058886","quote_asset_id":14,"base_asset_id":0}}},{"type":"update_feed_op_type","data":{"feed":{"feed_id":7,"delegate_id":18766},"value":{"ratio":"0.000124323783549378","quote_asset_id":7,"base_asset_id":0}}},{"type":"update_feed_op_type","data":{"feed":{"feed_id":22,"delegate_id":18766},"value":{"ratio":"0.001490020525769598","quote_asset_id":22,"base_asset_id":0}}},{"type":"withdraw_pay_op_type","data":{"amount":50000,"account_id":18766}}],"signatures":["1f6616c9788206f632eae3154714ca09fcf367c8511cd56129f530449f674ac86022bb4cd0b4993fda63b4420f21d7a714626bb7b31f91ba8bbb3196a9ae0b18b6"]}}
    th_a  transaction_evaluation_state.cpp:244 evaluate
    {"trx_num":0}
    th_a  chain_database.cpp:729 apply_transactions
}
but it seems to still be on the fork (compared to another machine)
Machine 2 (0.4.26):
default (unlocked) >>> info
{
  "blockchain_head_block_num": 1286385,
  "blockchain_head_block_age": "1 second old",
  "blockchain_head_block_timestamp": "2014-12-17T19:03:40",
  "blockchain_average_delegate_participation": "72.66 %",
  "blockchain_confirmation_requirement": 7,
  "blockchain_share_supply": "2,498,439,830.19030 BTS",
  "blockchain_blocks_left_in_round": 52,
  "blockchain_next_round_time": "at least 9 minutes in the future",
  "blockchain_next_round_timestamp": "2014-12-17T19:12:20",
  "blockchain_random_seed": "6e6343e36995b304269ba0bf45dfb9078c36c098",
  "client_data_dir": "/home/showard/.BitShares",
  "client_version": "v0.4.26",
  "network_num_connections": 10,
  "network_num_connections_max": 10,
  "network_chain_downloader_running": false,
  "network_chain_downloader_blocks_remaining": null,
  "ntp_time": "2014-12-17T19:03:41",
  "ntp_time_error": 0.00090200000000000002,
  "wallet_open": true,
  "wallet_unlocked": true,
  "wallet_unlocked_until": "3 years 2 months in the future",
  "wallet_unlocked_until_timestamp": "2018-02-13T03:46:55",
  "wallet_last_scanned_block_timestamp": "2014-11-12T00:42:40",
  "wallet_scan_progress": "? %",
  "wallet_block_production_enabled": true,
  "wallet_next_block_production_time": "49 seconds in the future",
  "wallet_next_block_production_timestamp": "2014-12-17T19:04:30"