It seems another extremely annoying 'feature' of this software... Never had an issue with other software when I choose an export of 23.97 FPS... For some reason, this software seems to do 23.976 (which gets rounded up to 23.98).
There is nothing to fix, the 23.97 the cause is the precision to which the frame rate is specified in this case the true framerate 23.976 round up to 2 dec places 23.98.
You are getting the 'odd' frames per second because you are in a NTSC TV standard region - these odd framerates are legacy values based on the framerate standard for old CRT type displays.
Modern TVs, mobile devices and computers will work with a range of frame rates and there is no reason why you should not record at 24, 30 or 60 fps.