Run / Debug Config Log Empty

For some reason, when my run log is not being written. I've configured the Run/Debug Configuration for a Gradle-based test to have the "Save console output to a file" checked.

The file gets written, but is empty (0 bytes). I thought it might be permissions (despite the log file being created) and chmod 777 just to see. No luck. Running out of ideas, I recreated a whole new Run Config from scratch, but got the same results.

I've used this feature a thousand times before, but must have messed something up.

My config:

IntelliJ IDEA 2017.2.1
Build #IU-172.3544.35, built on July 31, 2017
JRE: 1.8.0_152-release-915-b6 x86_64
JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
Mac OS X 10.11.6

Thanks in advance!