It's all about the Software

I was under the impression this is the SDR Console Software forum? SDR Console has this issue.

May not be a bug but an observation.
SDR Play RSPDX, Virtual audio (Voicemeeter Potato)

The filters appear to "leak" for lack of another word. Example with a 4khz default filter applied, the audio is roughly 100-4000, however there is a spike outside/above the filter range in the actual audio ...