Normalizer usage:
Fill the first insert slot with this plugin. Put the plugin that's supposed to cause denormalisation into the second slot.

The normalizer plugin lets you choose between two methods: adding AC or DC signal.
Here, AC is a square wave ringing at the nyquist frequency (half the sampling rate, e.g. 22.05kHz).
Choose this method whenever the following plugin does not apply intensive low-pass filtering, thereby eleminating our injection noise.
In that case, the DC method could be used. It just adds a static offset to the signal. This DC level (when set pretty low) should be no issue with further processing of the resulting output.

No matter which method you choose from, the noise floor should be lower than the lowest value that your D/A converter can handle.
And in fact, a level of about -300 to -200dB is usually enough. Sometimes you can even go much lower.

You will have to experiment with the proper level because the internal working of the faulty plugin is most certainly unknown to us.
The more stages it involves, the more complex the whole thing is.