A photo shot with an 1:1.8 lens contains the following exif data:
ApertureValue: 1695994/1000000 MaxApertureValue: 16/10
How is this possible? Both values are <1.8.
You are confused because ApertureValue and MaxApertureValue are APEX values, not F-stops.
An F-stop of 1.8 is equivalent to an APEX aperture value of about 1.695994. (The formula is Av=log₂A², where Av is ApertureValue and A is f-number. See the Wikipedia APEX system page for a full explanation.)
Some exif readers (like ExifTool) convert these to F-stops for the user, but others do not.