You are classifying ASVs. Just because two different ASVs (or even OTUs) have different sequences does not mean that they belong to different taxa. Different strains of the same species can have slightly different 16S sequences; even the same strain can have multiple 16S copies with very slightly different sequences. In your example, you are showing genus-level classifications. These different ASVs are all classified to the same genus — they could be different species in that genus, or different strains of the same species, or different copies of the same species! So overlapping taxonomic classifications is never a surprise.
Check out this tutorial. Better yet, try this command:
qiime metadata tabulate \
--m-input-file taxonomy.qza \
--m-input-file rep-seqs.qza \
--o-visualization taxonomy.qzv
That will paste together your taxonomy and representative sequences file into one, for easy comparison.
Good luck!