In rare cases CRC codes dont match when reading data from couch file

I experimented with building index on 6 cluster_run nodes and 9E6 simple docs. Everything went fine and results appeared right, but I'm seeing


[ns_server:debug,2012-09-05T21:31:14.218,n_5@10.17.21.241:compaction_daemon:compaction_daemon:schedule_next_compaction:1204]Finished compaction too soon. Next run will be in 30s
[couchdb:error,2012-09-05T21:31:14.296,n_2@10.17.21.241:<0.9681.0>:couch_log:error:42]Set view `default`, replica group `_design/dev_t`, doc loader error
error: {file_corruption,<<"file corruption">>}
stacktrace: [{couch_file,pread_iolist,2},
             {couch_db,open_doc_int,3},
             {couch_set_view_updater,load_doc,4},
             {couch_set_view_updater,'-load_changes/7-fun-0-',6},
             {couch_btree,stream_kv_node2,8},
             {couch_btree,stream_kp_node,7},
             {couch_btree,fold,4},
             {couch_db,enum_docs_since,5}]

[couchdb:error,2012-09-05T21:31:14.297,n_2@10.17.21.241:<0.6715.0>:couch_log:error:42]Set view `default`, replica group `_design/dev_t`, received error from updater: {file_corruption,
                                                                                 <<"file corruption">>}
[couchdb:info,2012-09-05T21:31:17.856,n_2@10.17.21.241:<0.6715.0>:couch_log:info:39]Starting updater for set view `default`, replica group `_design/dev_t`
[couchdb:info,2012-09-05T21:31:17.856,n_2@10.17.21.241:<0.9753.0>:couch_log:info:39]Updater for set view `default`, replica group `_design/dev_t` started


in logs. Will attach logs from this box.