Is there an option to eliminate AutoCAD from automatically inserting the layout tab name into the file name when creating a PDF? Once upon a time it would only use the file name (i.e. A-101). Now it uses "A-101_Layout1" (or whatever the layout name is) by default. I either have to live with it or manually change each file name during the process of creating the PDF or after it's been created.
I suspect you had a customization that did that for you (or pre-Layouts AutoCAD?): tab names are the default behavior (and work great for us as it is part of the file name/content).
I believe you can turn off auto-naming altogether with FULLPLOTPATH variable set to 0 (zero).