Saturation in V4 (2020) Filmic RGB

I have played with several ways to adjust contrast in dt and most recently I tried the “middle-tones-saturation” adjustment. In itself it appears to provide a major solution to my needs but I did cone across an oddity that concerns me. For some reason when exporting my image to JPG format the intensity of the saturation was entirely different from that shown on the screen in either the lighttable or darkroom modes.
I have carefully checked the softproofing settings … they look OK.
The problem was most noticable when I was using a fairly high setting and by ‘dial-back’ the value I did achieve very acceptable results.
Anybody else seing this problem at higher settings?

Is the app you’re using to view the jpeg color managed?

This was seen with an export to email and then the attachment was viewed in Geeqie.