2.8 Dynamic paint for weight map is broken?

i just did a dynamic paint set up for vcol, displacement, wave… and i had no problems at all. but for weight map it’s not working at all for me. i tried everything. can someone quickly see if it’s possible to do so ? am i the only one who have that ? is it a bug ? or am i missing something important ?

With a quick spontaneous try I found it working for me. If you post a blend file I can take a look what is wrong.

Normally, it is just the preview of weight that is broken.

Dynamic Paint is modifying weights of vertices ; but it is not visible, if canvas is set into Weight Paint mode.
If you add a modifier after Dynamic Paint and set weight group to influence this modifier : you should see weight modification done by Dynamic Paint brush animation.