for some reason, after the windows 10 upgrade. ligatures were auto enabled on all InDesign and Illustrator documents.
1. is it a known issue?
2. is there a way to reverse it globally without going to every single document and unchecking the box?
this is for CS6.
CS6 will never be updated for Windows 10. It's a small issue and you'll have to live with it unless someone creates a script to fix it. (Similar things now start to happen with CS6 on the newest Mac OS X operating system.)
I find it very odd that this would have happened from an O/S upgrade. The O/S doesn't touch the documents and ligatures are not only document specific but can be set for individual styles.