My son just started working on Tynker last week on Windows 10. We have a paid subscription.
Things seemed to be working fine with Minecraft for a while, but then he tried the "Giant Cake" exercise. He dove into custom modifications right away before deploying, but nothing happened. So, I had him back off to the suggested code. That also didn't seem to do anything. So, we started putting "say" commands into the code (think "printf?"). What we found is that the "/ty cake" mod got as far as the "build" command in the "make a cake layer" function, but (1) never built anything and (2) never exited the function (a "say" command at beginning and end of function, only the first one triggered).
Now, we are stuck. Any way to get farther? I haven't been following along with him recently, since he is pretty code savvy, but both of us realized that we don't know where the drone is. Does it follow along with the player?
Whatever the case may be, the build command is getting stuck (not exiting, not repeating multiple times).