FDS write failure

Question

Hi, 
 I am seeing some random behavior on FDS write: 
 1.sometimes it won't receive any callback for 2 seconds 
 19:57:49 - logMessage: "Fds_Write_Async 2" 
 19:57:51 - logMessage: "Fds_write timeout"

2. sometimes it won't find the exisiting the record, though the previous one was just read

19:57:55 - logMessage: "Fds_Write_Async 2"

19:57:55 - logMessage: "FDS event: type 2 ret 34313 record_id 6 file_id 1 record_key 2 update 0"

ret 34313 is FDS_ERR_NOT_FOUND

3. after a write timeout, the next write with a different record triggered the event for the previous record

19:58:52 - logMessage: " Fds_Write_Async 2 "

19:58:54 - logMessage: "Fds_write timeout"

19:58:55 - logMessage: " Fds_Write_Async 1 "

19:58:55 - logMessage: "FDS event: type 2 ret 34313 record_id 12 file_id 1 record_key 2 update 0"

Normally when it works I saw multiple event coming back(here I am updating the record):

19:59:11 - logMessage: "Fds_Write_Async 2"

19:59:11 - logMessage: "SD event received"

19:59:11 - logMessage: "FDS event: type 2 ret 0 record_id 12 file_id 1 record_key 2 update 1"

here is my write logic, all the writes are synchronized in the upper layer so they are happening in sequence: 
 // If data already exists, update it 
 if (fds_record_find(record.file_id, record.key, &record_desc, &ftok) == NRF_SUCCESS) { 
 ret = fds_record_update(&record_desc, &record); 
 } else { 
 ret = fds_record_write(&record_desc, &record); 
 } 
 
 Any idea what might be going wrong? 
 
 Thanks, 
 -Ray