This problem was discovered in the advanced search - when limiting by shelving location the search is composed as 
limit=mc-loc:{term}

this fails in ES because the index is setup as 'location'

What works in both is:
limit=location:{term} 

We either need to build field aliases into ES (https://www.elastic.co/guide/en/elasticsearch/reference/master/alias.html)

Or make sure to use consistent names across Koha