In the past I have been able to print front to back and in color. Recently, InDesign stopped holding both options at the same time. When I go to my printer menu to set the front to back printing, then go back to my Indesign print menu it turns to Grayscale. When I turn that back to color I lose the duplex option. Is there a setting I need to change to get them both to work at the same time?
InDesign has never been known for superlative printer support.
However, the first thing I would check is to make sure your printer driver is up-to-date by going to your printer manufacturer website.
Has anything else changed in your system configuration? What operating system? What version of InDesign?