I hit a roadblock due to this limitation yesterday - distance maps will not work with transform motion blur (camera motion blue works fine) - and in my case the workaround is a really painful one - instead of just using the Distance Map I need to bake color maps for 100 objects.
Hopefully, this limitation can be lifted since using distance maps solves a lot of work in some cases.
Attaching an image showing the problem and a scene - max 2021, Corona 7.