After upgrade, the MTA Live Monitoring only partially reports the emails with status "Scan Started", while all the emails are logged correctly from the RAW log and Smartlog index.
...... SolrException: ERROR: [doc=6302ceee-62e4-2a0f-88e2-8b9718f49c4b] multiple values encountered for non multiValued field file_size: [43081, 0]
....
DATE TIME,PID ERROR [qtp1506885426-335160] org.apache.solr.core.SolrCore.finish:73 - [1] errors found for message [ERROR: [doc=6302ceee-62e4-2a0f-88e2-8b9718f49c4b] multiple values encountered for non multiValued field file_size: [43081, 0]]
Cause
SOLR failed to index some of the MTA logs contains file_size in multiValued field.