Part of the debugging process is being sure of each assumption before moving on. Reporting the version number of the actual script you are running would be helpful.
In our tests the v7.35 version of the script, it correctly creates the images when running the script and specifying 25% scale. The settings I used:
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If you are running the same version of the script, then we'd need the PSD you are running the script on to try and reproduce the problem so we can fix it. You can email it here, we will keep it confidential: contact@esotericsoftware.com