I'll explain the way I like to frame User Experience and Usability Bugs, hope it is useful.
First of all, I like to group all bugs, undesired system responses or behavior into technical or design debt. Some issues might fall into both, but they are equally debt and should be eliminated promptly because additional rework is very costly. If we only fix an instance of an issue or bug, it is simple, but the debt is not eliminated. For that reason, I take a different approach to documenting debt in general.
Start with outcomes
The goal of reporting any bug is that they will be fixed, once. To ensure this happens, I need to be able to understand not only what is wrong but also why it is wrong and the context where this is happening.
So now let's imagine you have identified a bug:
Users see a warning label on the shopping cart icon while doing the
checkout of an item.
An outcome for solving this would be:
Minimize [distractions] by [system warnings] when [doing the checkout
of an item]
In this case, the outcome has a direction (minimize) a unit of measure (distractions), an object of control (system warnings) and a context (when doing checkout).
So now I can categorize this into Distractions (design debt) and System Warnings (technical debt).
Keep in mind that what we choose to measure regarding the user experience will depend on the nature of our product or service, but I've found almost anything will fall into intuitive categories once we apply the outcome formula.
Separating solution from the reported issue
I'd personally find it difficult to include the solution in the title because I believe it's complicated to know what exactly will solve the issue beforehand. I prefer to separate my thought process into being problem-aware and solution-aware.
When reporting the issue I can only be problem-aware, this is the limitation I'm working with, so instead, I will describe the measurement of success. What will success look like when I close this ticket and when will I know that?
To get the problem from an issue description, I like to ask myself why this is a problem and iterate until I get as close as I can to the root cause of the problem.
So for your example:
Clicking on X closes the whole page.
Why is this a problem?
Users don't expect the whole page to close when they click X.
Why is this a problem?
Unexpected response when clicking X is preventing users from
Which will be reported as:
Unexpected response when [clicking X] is preventing users from
Measure of Success
A week after closing this ticket, we have 0 users abandoning [goal]
due to an unexpected response from clicking on X.