Error messages spamming in logfile.

I have a RT-AC68U. Yesterday i flashed with the last version Asus stock firmware .45708 version. I did this with the UI. After i while a message appears: server not available. The router hangs up, so i rebooted after a while. Router started up normally, and i tried again with the interface. The normal thing happend, he flashed to latest firmware and started normally up. But when i see the logfile, it shows continues error messages:

kernel: SQUASHFS error: xz_dec_run error, data probably...

Error messages spamming in logfile.