Why does Permanent work some days and for some parent tasks, but not others? This happened last week, and again today. Permanent Link works on tasks I don't need it for, but not the one I need to use it on. I've posted this same problem some time ago.
I know the TD staff focus is now on Lists and Outlines, but they need to take some time on fixing tasks so the existing features work.
We have tried a number of times, but we have not been able to reproduce the problems you are having with permanent links. Perhaps you could open or reopen a support ticket with step by step instructions for how to cause the problem that you are having.
Next time you click on a permanent link and it doesn't work, refresh the page. (via F5 or TD keyboard shortcut "R" or the mouse) I bet your desired permanent link will automagically appear.
You can reproduce the bug like this:
1) Go to the search view
2) Select a Saved Search
3) Launch any task via Permanent link
4) Using your mouse, select the saved search from step 2.
5) Try to launch the permanent link from step 3. No worky.
6) Hit F5 and the permanent link will launch.
What happens: After Step 3 you will see the unique URL in the browser address bar. When you click on the saved search in step 4, that URL doesn't change as long as you remain in the search view. The bug happens when you try to "go to" to the page you are "already on" according to the addressbar. You can reset things by clicking on anything in "View By" in the upper left... including "Search".