PCF2129 reset line prevents boot


I have a custom board with an MT7621A and also a PCF2129 RTC. The external system reset line of the PCF2129 is tied to the MT7621A reset line. This was working perfectly but after updating from OpenWRT 19 to OpenWRT 22 we see that the board sometimes doesn't boot.

We traced this back to the bootloader not even trying to boot the kernel because the reset button was pressed during boot which causes the bootloader to go in upload mode.

This only occurs after a power loss of the system and only in some cases. I suspect that the watchdog functionality of the RTC is triggered and it keeps the reset line low. In my opinion the device should only do this for a second or so and then release the line again. Have their been any changes in how OpenWRT uses external watchdogs which my explain my problem?

Kind regards,