in general, yes .... It can however happen that some application is using the share and alters the permissions , or if MIXED security mode is used , and a CIFS user connects, the ACLs from CIFS will replace the Unix permissions, in which case the export goes haywire ...
To find the root cause, some more background information is needed , also :
it could be , and this is a _could_ , that a user connects to the /home/data and runs a cown command , for whatever reason, maybe to stop clients using the share simultaneously ?
Very thanks your kindly help ! But I found the root cause and here is the status
We used Linux computer as a router to control the IP address mapping & routing but one of our people just replaced the HDD (backup from other Linux computer) and forget to put the correct IP address mapping so it have IP address confliction problem. Because the phenomenon is very very wired that is why we can to find the root cause immediately.