I know, the notation window was one of those features brought to the party late on the OS X version of Metro, but I still felt I ought to pass along the strangeness.
The Setup:
On a fresh, clean, new Metro document, open up the Notation window to the right of the Graphic Editor. That was easy, wasn't it?
Steps to Repeat:
Put notes on the staff in the Notation window, in this order: dotted quarter, eighth, dotted eighth. The last one will appear instead as a quarter.
Note the Graphic Editor window. It shows that the last note placed was a dotted eighth in length, starting at 1:03:000.
Place another dotted eighth note on the line, and it will appear as another quarter, and it will start a new measure. Over on the Graphic Editor window, the note you just placed starts at 1:04:000 (not 1:03:288).
That's the part that should definitely not be happening.
Delete those artificial quarter notes. Go to the Graphic Editor window and lay out proper dotted eighths (and an eighth to complete the measure). What appears on the Notation window is disconcerting, but on the other hand I could see where it would be notationally sound to group notes in that way.
That's the part I'm not sure about. It may be behaving correctly, but honestly it came as a shock to see.
This is happening on 6.3.2.3 (the latest prerelease version), and I'm running a PBG4 1.67GHz with 2Gb memory and plenty of free disk space. Screenshots are available on request. I don't have them yet, but this is a repeatable phenomenon.
Please let me know if there's any other information you need.