That is a function of the fixture and will highly vary based on actual use. It is a resonance due to volume of the tube in front of the measurement mic. My GRAS fixture "high resolution" coupler suffers far less than typical coupler but it is still there:
View attachment 417117
These are the variations you can get without the damping in my fixture:
View attachment 417118
It is therefore impossible to know what resonance there is in real usage.
As I have said though, lack of standards in music production means you don't know if what is there is already exaggerated, neutral or diminished so there is no good solution here other than per track equalization or just ignoring it.