Wired in a timer for a bathroom fan (the type where you can selected 5min/10min etc and it shuts of after that). In the "wall box" was a single wire group, with a White, Red, Black, and Ground (bare). The White was Hot, Red was cold side for fan, Black was cold side for light. The timer switch had a Hot (black), Cold (red), Ground (Green), and Neutral (white). The only way I could get the electronics of the switch to work in conjunction with the light switch was to route the Neutral (white) on the switch into the Ground (green) which was already connected to the box ground screw and bare wire ground from the box. Is this wrong, and can it cause electrical issues? If I ran the Neutral wire to the Black (cold for light) it would work, but then when that was energized by flipping the light switch it would shut off the fan.

The only way I could get the electronics of the switch to work in conjunction with the light switch was to route the Neutral (white) on the switch into the Ground (green) which was already connected to the box ground screw and bare wire ground from the box. Is this wrong, and can it cause electrical issues
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Yes that is wrong and yes that can cause electrical issues.

What you have is a switch loop. The white is bringing power from the ceiling box. (It should have a piece of black tape on the end of it to designate it as a hot.)
The black is returning power through the switch to the light. The red is returning power through the switch to the fan. You do not have a neutral at the switch box. The timer motor needs a neutral to run. You are not allowed to use the ground as a neutral.

Ok, then ill have to change it. Thanks for the info... back to a basic switch it is.