No problem with generic, except I have more money in my pocket.
My INR is more affected by whether or not I drink, and exercise, than by the brand of medication. and some people are not affected by drink or diet.
I recently gave up alcohol and chocolate for about 3 weeks trying to shed a few pounds. Boy, is my INR stable. 2.5, 2.6, 2.6. For me that's unusual. And about .5 lower than weeks when I have a few glasses of wine. If I keep teetotalling, I may have to add a mg to my dose next week! But that's me.