For the channel values got resetting, (unless things have changed) AGS can only use colour values in the 16-bit space (even if the game is set up to be 32-bit), so that all the colour channel values would be snapped to the 16-bit range, i.e. you cannot use precise 32-bit values for raw-drawing and speeches, etc., and only approximate values can be used.
Also, the colours for the lower indices(couldn't remember how many, probably #0-16 or #0-20) are also hard-coded, overriding the "correct" colours(as far as I remember, the "pure" blues) in 16 or 32-bit modes, so you cannot get accurate pure blue colours. A workaround is to add some slight red and green to the other two channels.
Also, the colours for the lower indices(couldn't remember how many, probably #0-16 or #0-20) are also hard-coded, overriding the "correct" colours(as far as I remember, the "pure" blues) in 16 or 32-bit modes, so you cannot get accurate pure blue colours. A workaround is to add some slight red and green to the other two channels.