Hi r3nt5ch3r, it may be possible the mod has a memory leak, although I believe everything should be reset when any mod or settings are changed so in practice it shouldn't be too much of an issue if there is one; I'll look into this soon and release a fix if needed.
For a little context about the big storage size, the drop location of the inserters can only be accessed via the inserters, not the belt/machine/entity they place onto. So to enable inserter highlighting for inserters placing onto a belt, I have to store each inserter indexed by drop location so that they can be accessed from the lookup table when tracing the belt. At some point in development I did some rough math and figured that the storage size probably wouldn't be an issue, but since you're posting about it clearly I assumed wrong! I'll look into finding some alternate solutions.