I have 2 razors (2018) and it seems the sonars get about 2/3 years out at most. I've replaced both on my machines and I keep one spare on hand due to this being such a waste of time/chemical when it fails it was worth it for me to have one on hand. As many said, that's most likely your issue, if you have another bay swap it over and see if the problem stays there or not. That is the same sonar that I have on my machine, I would thing they'd last longer than 2 years being my old Superior from 2004 would last 2/3 years as well on those sonars, 15 years of technology apparently they still have a limited life expectancy.