Bug with Overwrite and persisting IO points. Fixed in 17.1.1

Blank timeline.
Set I and O points on the timeline
Set a single I point on the source.
OVERWRITE.
I and O points remain on the timeline
Same with source I and O set and only I or O on the timeline
Do an INSERT and they disappear as I thought they should with OVERWRITE.
Have I toggled a weird setting somewhere or did it always do this?
All prefs in PREFERENCES>EDITING>USER are toggled off.
Nothing like a rainy afternoon to start to doubt one's sanity.
Screen shot shows result after OVERWRITE command.
Set I and O points on the timeline
Set a single I point on the source.
OVERWRITE.
I and O points remain on the timeline
Same with source I and O set and only I or O on the timeline
Do an INSERT and they disappear as I thought they should with OVERWRITE.
Have I toggled a weird setting somewhere or did it always do this?
All prefs in PREFERENCES>EDITING>USER are toggled off.
Nothing like a rainy afternoon to start to doubt one's sanity.
Screen shot shows result after OVERWRITE command.