Kdenlive 16.12.0 will see further improvements to its library clip expansion (and, in consequence, to MLT playlist import). Not every Kdenlive user will notice the improved functionality, as it affects only library clips where the same image sequence or title is used multiple times.
In particular, if you (re) use the same image sequence clip, title clip, or even color clip multiple times in the same libary clip, such image sequences and titles will only be added once to your project bin. Before Kenlive 16.12.0, multiple instances of the same clip in the timeline unfortunately resulted in these clips getting added multiple times to the project bin. To emphasize, this undesired behavior only affected image sequences, titles, and color clips.
When expanding a library Kdenlive 16.12.0 will now check image sequences, titles, and color clips in the timeline for their content, clip name, and original bin folder location. If there is a match, then such a timeline clip will be added only once to your project bin.