Apparently G54-G59 codes can not be in the same line as XYZ codes.
Now working Example:
G55 (Where Offsets are x-9999 y -9999)
G54 X0 Y0 (Machine still in G55 will try to move axis. This will fire the overtravel error)
But this works:
G55 (Where Offsets are x-9999 y -9999)
G54
X0 Y0 (this is fine)
Why this matters: most CAM software by default generate code like: G0 G90 G17 G54 X.. Y..
Which will fail or crash the machine if the current offset is different from the programmed one.