This is for the Loudness Normalizer processing function. This occurs whether using the batch processor to normalize files or doing so with individual files.
If a mono 16bit 44.1kHz file is smaller than 30kB in size, then the loudness cannot be accurately analyzed. If the file is normalized with the processor anyway, then the process will arbitrarily raise the gain on the file and this results in the file getting clipped and becoming distorted.
The expected result is that if a file cannot have its loudness analyzed properly, then the processor should not attempt to process the file.