The laser only cuts part of the tool-path leaving gaps. Some vectors are missed or appear to be partially cut.
See photo below.
The most common reason for this is either the feed-rate is too fast or the laser power level is too low for the material being cut.
Slow the feed-rate down and/or increase the laser power. Re-run the job.
A good guide is to start with a feed-rate on 500-1000mm/min and laser power at 75%.