You mentioned that before here "Single Band Parametric" occasionally losing "Enable" - #18 by DickN Can you hear the difference in fractional frequencies?
I think it is simply the result of us now validating plugin input. You can see if you click in (or arrow through) the Frequency slider that the values in the text box are integers. The LV2 version of this plugin GitHub - swh/lv2: SWH Plugins in LV2 format shows fractions when moving through the slider (observed on Ubuntu 14.04).
So you could try compiling the LV2 version of the plugin. From memory, compilation on Windows does not work out of the box (but I never tried that hard). If necessary, you could encourage Steve Harris (the author) to make it work.
Gale