A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
I can confirm the impression you have but the actual Row Height does appear to be correct. It looks like the indication on the Vertical Ruler is what is inaccurate. To confirm this I created a rectangle Shape & set its Height to 4 inches & used Format> Row Height to specify 4 inches as well. When aligned with the row the rectangle spans top to bottom of the row perfectly but the marking on the ruler indicates 3.75". I'd consider this a bug.
Please use the ☺︎ at the upper right corner of a workbook window displaying the conflict to submit a ☹ explaining the issue & include a screen shot. I've done the same.