Duplicate and splitting leads

Duplicate and splitting leads

I'm trying to diagnose an issue that is either a bug or a workflow issue on my end.  On a selective basis, records are being duplicated and information is being split between the two records. I'm not sure if there is an import/export bug or something done on our end.  

A little simpler, some leads are being split into two leads with data being separated between them. I'm not doing this manually so I'm leaning towards a bug.