why does not show real finish copy files into sdcard in konsole or dolphin?

when i copying files into sdcard show message finish copy but real not finish copy files still copying files after two minutes finished
for example

dd count=500 bs=1M if=/dev/zero of=/run/media/~/C5E5-0AFD/test.img                        
500+0 records in                                                                                                                 
500+0 records out                                                                                                                
524288000 bytes (524 MB, 500 MiB) copied, 0.566918 s, 925 MB/s

But in fact it is not true still copying and wink light sdcard
Why does this happen?

Run the command mount at look at the mount options for the sd card (hint to see what they mean, man mount). Filesystem type, buffers, caches etc since they are slow, it takes time for the data to write (with integrity) to the device.

If you want ‘dd’ to only report back when the flushing is done, then add
‘conv=fsync’ to the command, as that will cause all of the sync stuff to
finish before the system returns.

As malcolmlewis mentioned, drives are slow, so the OS and other things
will cache for you for performance reasons, though that means you must
account for that when you want to test actual speeds of disks.

Good luck.

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Thank you for tips.