No Run/Walk alerts while doing a Run-Walk-Run Coach workout?

I am doing the 5k program from Garmin Coach with Jeff Galloway. The program is based on a Run/Walk strategy. But when I setup Run/Walk intervals for the running activity on my watch, it does not activate during a run from the Coach program? 

There are threads dating about half a year back for the VivoActive 3 that seem to have the same issue. I guess it is (still) not working as expected. Anybody else have this issue, or better yet: does not have this issue while doing a training from the Coach program?