As far as I know, materials design doesn't mention these badges to go on the Bottom Navigation View, so there isn't any authority here as to what the "right" thing to do is. I think that it should align to the left. I feel like raising an issue is the bet place for that discussion!
(I've deleted the other two icons from the screenshot.)
I'm not 100% what the right behavior here is, but I think most things that were aligned to the right (e.g. the FAB) alight to the left when using an RTL locale (here, I'm using AR (XB) from https://developer.android.com/guide/topics/resources/pseudolocales).
However, the badge is aligned to the right still.
As far as I know, materials design doesn't mention these badges to go on the Bottom Navigation View, so there isn't any authority here as to what the "right" thing to do is. I think that it should align to the left. I feel like raising an issue is the bet place for that discussion!