These flag values have both ends mapped, but not properly paired. The properly-paired/aligned flag is described as

each segment properly aligned according to the aligner

which is not enormously clear, but typically means that the reads are mapped with appropriate orientation and insert size such that they plausibly reflect the whole template having been "nicely" mapped as a whole to the reference.

So having both ends mapped but not properly paired means that they have been mapped with either implausible orientations or an implausible insert size.