Android testbuilds fail because of the too early MOZ_BUILD_DATE

I've just tried to run an Android testbuild, but it failed:

FAILURE: Build failed with an exception.

* Where:
Build file '/var/tmp/build/firefox-android-e77cf21baa62/fenix/app/build.gradle' line: 308

* What went wrong:
A problem occurred configuring project ':app'.
> java.lang.RuntimeException: Cannot calculate versionCode. Hours underflow.

so I checked the build script and found:

export MOZ_BUILD_DATE=20000101010101

I wonder if this cutoff (from /var/tmp/build/firefox-android-e77cf21baa62/fenix/buildSrc/src/main/java/Config.kt) is the problem:

format.parse("20141228000000")