Your comments

I had no problem with the automatic updating function.

Found it!

When I added an action to a project (directly when creating the action), the project list of action was not updated until I locked and unlocked Wieldy once. However does this not always occur. Probably an UI update event required somewhere.
Something odd happened yesterday but I have not yet been able to recreate it. It was in the flash of an eye so I don't even no exactly what happened...

I will check more cautiously the next days to see if it happens again.
This is another example of a method-breaker. GTD is just a method to organize what should be done next, not a project follow-up or timelogging tool. There are some really great tools available for time-tracking (Grindstone is one example, I use it at work), that you should use in stead.
GTD is not really about how much time you spend on a task (unless it is shorter than 2 minutes, then do it at once) it is about knowing what to do next in the right context.
I'm not certain that it should at all be possible to sync Wieldy with task list managers at all. Just because that would break the GTD strict planning concept. A task list is just that, a task list. But GTD is a method!
Why not just add a read-only project reference in the action data that is displayed when you unfold (expand) the action? At least for now? It is impossible to know to which project actions listed in the Next view belong and therefore one must check all projects (20+) for which project to work on.
Kevin,
Yes, it did import but the project list was not updated until after I restart Wieldy. So it seems as if an UI update event of some kind is still missing.
Yes, I agree with Winfried. I utilize projects a lot and often add tasks to be done later as a reminder. But I cannot 'deactivate' such tasks in a proper manner to avoid having them on the Next list until it is time to do them. There shall only be one next action for each project if you use GTD properly I believe.
I have between 5-25 projects running all the time, so just identifying projects by color is not as useful as to see the project ID. I believe Dave Allen mentions that a large number of projects is quite common when working professionally with GTD.
Yes, I concur, I use these fields a lot for @Work projects. There should be a project details list shown when you click the Projects item in the navigator of project objects just like the list of actions for a certain project.