Sometimes with lncrnas the structure is what is more important than sequence. You can have two lncrna with different sequence but the same kmer structure. This makes logical sense as while proteins often bind to specific sequence the reasons for that are merely structural. In protein you can also have conservative missense mutations that are tolerated as binding affinities may not have changed swapping out an amino acid residue for another with the same charge or polar properties.

https://pmc.ncbi.nlm.nih.gov/articles/PMC6262761/