[case 1]
Created file ‘a’ on A.
Modified file ‘a’ on A.
after few secs, I modified file ‘b’ on B.
in this case, B’s file has been synced to A.
[case 2]
Created file ‘a’ on A.
after few secs, Delete file ‘a’ on A.
after few secs, Create file ‘a’ on A.
after few secs, Delete file ‘a’ on A.
.
.
.
repeated few times.
.
.
after few secs, Create file ‘a’ on A.
after few secs, ‘a’ file deleted from A.
I understand that sync point is modified date / size / right.
I cannot understand case 2, file ‘a’ last modified date is maybe A’s time.
Modified date is mostly meaningless to us, and is only used for deciding conflict winners. System clocks are not accurate and can lead to data loss.
Deciding which file is newest/conflicting is decided using vector clocks, you can go read about them on wikipedia, but the tldr is that it’s the file that is newest given the existing lineage information.
Not sure what your actual test is, but if all of your changes are made from one device, I would not expect the other remote device to have any effect on the file state assuming the other device is not modifying anything (and assuming the other device is not some sort of android device or other device with a poor filesystem consistency guarantees).