I am challenged to understand the manual shifting action of my new-to-me 2013 Titan SL with console shifter.

Specifically, with regard to manually down shifting from Drive, the "gated" shifter is first moved from the "D" position, to the left, into the "4" position.

The thing is, this doesn't appear to cause the transmission to actually shift. Also, the digital gear selection indicator on the instrument panel does not indicate "4", but continues to show "D".
The transmission otherwise behaves well.

My question is.... Is this 5-4 shift behavior normal or does the transmission require attention?