I have an issue where my Alliance is helping me speed up the building timer but it seems to then stay on 12/12 and not complete the building process until the timer has actually run its course. I have just recently changed alliances. Not sure if that has something to do with it or if it is a program bug.
This is intended behavior. Filling the help progress bar only indicates the number of people within your alliance that have helped you with your task.
For instance, start with 0/12. When 6 people click help, that will update to 6/12. And finally when all 12 people in your alliance have helped, it will show 12/12
The difference is that the help only gives 1 minute of reduction of time, so if your task is a 20 minute long task, and 12 people help, thats 12 minutes reduced from the total task duration. 20 - 12 = 8 minutes, so you'd have 8 minutes left before the task is complete.
Also, the number of helps is governed by the level of the Stronghold. I believe the formula is 4+the stronghold level, so if your stronghold is level 10, you can have up to 14 helps.