I just had a case of Schrödinger's error

I just wanted to share a little story of my day. I'm working on a Java Embedded application (subset of Java), and I was tasked to figure out how to run proguard on it.

I wrote the gradle tasks, run the application and all of the telemetry fails. Nothing is being logged to the server.

So I add a line to print any error code to the screen. Run the application again, and the telemetry works again, no error is being thrown and everything is being logged to the server.

I remove the same line, and the application just stops.

I check the diff in the decompiled code. There is exactly one difference, the print statement.

So yeah, no clue how to debug this, because I got Schrödinger's error