Rails logger level changes to ERROR abruptly

I am experiencing very strange behavior with my Rails logs. Wherein the logger level automatically/abruptly changes to ERROR(:error. logger level code 3) instead of whatever it was supposed to be (:debug or :info).

Here in this image the log level is as expected. Debug or level 0

But within few minutes(at most 2 minutes) the logger level changes to 3(3 stands for ERROR)

I came across a github issue which explains Rails logger is not thread safe, I am using passenger in thread mode as opposed to process which it was previously. Could this be a reason for such behavior ?

What could be other possibilities, that changes the logger level from 0 to 3 ?