I see the same issue, here's additional info if it helps.

The FITS header is correct for my guide camera & scope

PIXSIZE1	= 3.750000E+00 / Pixel Size 1 (microns)
FOCALLEN	= 3.00E+02 / Focal Length (mm)                              
APTDIA  	= 3.00E+01 / Telescope diameter (mm)                                            
SCALE   	= 2.578750E+00 / arcsecs per pixel

The FITS header is INCORRECT on 3 out of 4 values for my main camera & scope
PIXSIZE1	= 2.400000E+00 / Pixel Size 1 (microns)  <= this is correct
FOCALLEN	= 3.00E+02 / Focal Length (mm)           <= should be 1260mm
APTDIA  	= 3.00E+01 / Telescope diameter (mm)     <= should be 200mm
SCALE   	= 1.650400E+00 / arcsecs per pixel       <= should be approx 0.4 arcsec per pix

Attached is a screenshot of the Ekos telescope panel showing the correct scope values (focal length and aperture), and the Ekos debug log.

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