DRS With FISI cars

I notice when driving with AI using the Formula ISI cars, that the AI have DRS, but it will not work on MY car. I have a button on my wheel assigned to "rear flap" which SHOULD be for DRS. Am I doing something wrong?

 

Hmmm, works fine for me. Does it try to open the flap at all? Is this in a race or practice?

 

I haven't tried in race, but I know it doesn't work for me in practice..It used to work in earlier builds. Very strange.....