Bugs should be stories too!

The application we are building is not so fast anymore. So I entered an issue in our bug tracking database. After a while the bug is prioritised by our product owner and later in time the bug is placed on scrum board. Good practice you say. Nobody likes known bugs, they should be solved as fast as possible.
 
The fix for this bug was not that difficult. At least for the programming side. It just was to make some calls asynchronous and the complete program behaves faster. There was also some little impact in testing, because only a few interface functions where changed.
 
While fixing the tests, we discovered that everything was impacted. Our system behaved completely different as before. It was not wrong, but our test system needed to update.
 
Why is fixing the test code taking so long? It is not that difficult? No?
No, it is not difficult to fix the tests, but it is a lot of work. So the planning for this task is not correct.
 
What do we do if a bug gets on our board. We never refine bugs in a refinement meeting like the other stories. We only put them on our board. Look if there seem to be a lot of fixing time. Then we put 2 story points on it. If there is nearly no fixing time, it gets 1 story point.
 
I am not a fan of this approach. I do want to see the bugs, if it are not quick fixes, in a refinement meeting. They can have a lot of impact. Maybe the impact is only in the implementation. Maybe the effort is in our regression tests.
 
In my point of view, a bug is just like a user story. So we should threat them as stories too.