ArcGIS10.3.0 - suddenly I cannot get rid of field aliases in the select and field calculator pop-ups. This is particularly an issue in joined tables because the joined table names do not show up in the field list, only in the select statement. I have the aliases turned off in the tables. What now?
There is a protracted document on field aliases that needs to be read to see where alias settings apply and how to control them for the data source you are using... Unfortunately, you will have to read through it to see where your situation fits in
Understanding field properties, aliases, and table display options—Help | ArcGIS Desktop