Yeah, with the Raspbian os always got read only os after boot. We have tested with 5v 5a switching power supply, voltage is measured, and no sd card because installed to emmc. If you want to test please say it, I am holding some OPIs with the Raspbian os for testing purpose.
OK, I get the error log from dmesg just after the error, please take a look (OPI is up if you want any test):