We ran in some strange problem after the upgrade of OTRS4 to OTRS5. Somehow something changed and the a_from table of the table article is missing. This yields the problem that the from field in a ticket seems not to be shown. To be more explicit I included screenshots. Currently we're running OTRS 5.0.8.
Bigger photos @ https://www.anony.ws/image/JYam and https://www.anony.ws/image/JYag