It’s a common problem when you’re dealing with a flame, not a knife. Any time you have really tight lines that are being burned right next to each other, the potential for thicker lines exists. The places where the path turns on itself tightly is always going to be darker/thicker, because the machine has to slow down to make the turns. (The beam stays in that spot longer, so it burns a little more.) And the area is already hot. It causes more flame.
Using masking on the material is going to cut that down a lot. Once you peel the mask off most of the charring comes with it.
If you really want to adjust for it in a special design, you can place a break in the path in tight corners…frequently that will cause the motion path to move around and come back later to attach the previously cut segments.
Or, make the segments different colors and let the first set cool for a minute before running the second set without moving the design or the material.
That would be pretty extreme for this floral kind of design…you might just want to try masking and see if it helps cut that effect down enough. 
