Movement mode can be incremental or absolute.
Words can be modal or non-modal. Modal meaning "remembered" and applied to the next command word. Non-Model meaning they are not "remembered". The ANSI standard specifies which operations are "supposed" to be but some makers may not adopt these standards.
For some controllers, they remember what the last movement mode and/or word (and possibly direction) was so if you have not set or stated in a command line exactly what the machine control command is to do, it might be operating from previous command words. For example, if you said move -50, depending on incremental or absolute, the reference point will move either another -50 from current position (incremental) or go to the -50 (absolute) position from where zero was set.
A typical startup sequence to set a control into a "known state" might be as follows:
N10 % (SOF Header Start)
N20 (POST PROCESSOR: MACH2-3) ( SOF PostProcessorName)
N30 (X.NC) ( SOF by: HarryE)
N40 ()
N50 (SOF Machine Setup)
N60 G21 (SOF Measurement Units: MM)
N70 G00 G17 G40 G49 G80 G90 G64 (SOF CanOffsets+ConstantVelocityMode)
N80 ()
Note the G90 - set the machine to absolute positioning.
Also, if you used a G00 (Rapid move) versus a G01, the former says to move at the programmed rapid (max) move rate rather than a (possibly programmed) move at some much slower cutting rate.