There are reasons why I have users do factory resets and yes these are valid steps in troubleshooting as we have seem many issues after doing FW updates.
For security reasons, there is a timeout, if this is not a good solution for you then you'll need to find other means to work with it or find a different router. 3 minutes is usually the standard for all D-Link routers and is not a bug.
If your not willing to perform some of the suggestions or provide feedback to questions presented, then you'll need to phone contact your regional D-Link support office and have them help you sir. This forum is for help with immediate configurations, troubleshooting and setup. Anything beyond that needs to be addressed by D-Link engineers themselves, if there is a problem, as we can not effect any code fixes here in the forums.
Good Luck.