Mapping Conflicts when re-indexing using a template

I'm attempting to resolve a mapping conflict by first uploading an index template with the mappings for the relevant types explicitly defined and then re-indexing my documents.

However after re-indexing the field is still showing a mapping conflict when viewed in Kibana.

Q1. Could the mapping conflict be caused by the data in the field? i.e. if I am trying to map a field as a geo_point and it receives string data what does it error?

Q2. Any tips for finding the cause of the mapping conflict? Is there a way to search or see which documents have different mappings for the same field?