Photoshop CC 2019 bug: Pressing the up or down arrows in a numerical text entry field in the "Export As" dialog, whilst holding down the SHIFT key, adjusts the numbers in 5s, rather than 10s.
I just updated to Photoshop 20.0.2, and I can confirm that this bug is still present, and has not been fixed. To clarify, this would be in the JPG Quality settings field, where it adjusts in 5's. Changing the Image Size Scale percentage works fine, as this DOES increase/decrease in 10's.