I've seen several threads on this, but it is new to me since I updated to version R53.26 Build 27.1.53.26.
I also experienced the custom dates not saving, so reverted back to the old interface which seemed to fix this problem, but NOT the column width issue.
It's extremely frustrating to have to reset the columns every time I use 1 of my dozens of saved reports!
I'm running Classic Premier on Windows 10