I select text in a textbox in an open document, go to any of the value input areas on the toolbar (space after, kerning, etc.) input a value, hit tab or enter and the selected copy in the document changes to that value instead of reflecting the layout change for that value. Is this a bug or has something changed in 2017 and I'm inputting wrong?
That's a now wellknown bug with the Paragraph panel.
There are some workarounds:
A. Activate the Application Frame
Window > Application Frame
( That's my recommendation. I would go for this. )
B. Uncheck one or two preferences showing the OpenType Adornments with selected text:
Preferences > Advanced Type > [ ] Show Adornment on Text Selection/Text Frame for more Type controls
C. Use the Control panel alternatively to the Paragraph panel
But also note, that some reports came in, that also the Control panel can be affected if Application Frame is not used:
And also the Color panel could be affected ( not the Swatches panel, though ):
In the meanwhile there is a bug-fix for this problem.
It does not come along with an update notification from the CC Desktop app.
The fix is a separate installer you can download here from this Adobe Help page:
And when we're at it and you are on OSX having trouble with the Hyperlinks Panel see also here: