heapusage | Find memory leaks in Linux and macOS applications

I am using Heapusage, an alternative to Valgrind. When I am printing my linked list in the main function, it produces memory leak (when the printing function is commented, it is all fine). I was trying to find out what is wrong, but the printing function is so simple, that either my heap analyzer is bugged or the problem is so simple, that I can't find it.

I have a plot that shows the memory usage of some function over time, for two different versions of the function. Now, for each version I added a dashed regression line. So I added a legend (with scale_linetype_manual) which clarifies that solid lines represent the actual measurements and dashed lines represent the regression line. However, there is something wrong with the dashed line in the legend and I can't find out what is causing this:

The problem is more clear when i use a dotted line for the regression line instead of a dashed line. Those smaller extra dots should not be in the legend:

Here is the relevant part of my R script:

I'm trying to use heapusage to find memory leaks in the version of mencoder I'm using (as it happens 1.3.0, the most recent release).

mencoder was built locally, and was configured with '--enable-debug'.

The heapusage output looks like this: