This is the first time I heard of such an issue.
My suggestion is that Sequential should be the default.
Sequential is the default option in factory default settings. For example, if you perform a hardware (i.e. EEPROM) reset, it will turn sequential on. Can you think of any correllations of the 5 times it has been turned off? Also, next time this happens, try to restart the controller and see if the sequential is still off after restarting. This will help us tell if it’s the value stored in non-volatile memory that’s modified, or it’s the run-time variable that’s modified.