Snap doesn't work for markers of the currently moving clip
If the moving clip have marker, it's marker wont snapped to anything, neither other clips' markers nor end or beginning of other clips.
In the following image, I try to move blue clip. This clip gets snapped for its beginning and end to other clips beginning and end as well as to their markers. But the marker in this clip doesn't get snapped to anything else.
Kdenlive version 20.04.0