First, you get that message because the system will not allow you to post a new item until you have search for any existing items. You may not be the first person to have this problem; a ticker may already exist about this problem, and you should add to it rather than start a new one.
After searching, if you do not find anything related to this issue, either in Lesson or for other tools like Quiz or Gradebook that could have this problem, then create a new issue.
You only need to put three things:
1) The version of Moodle this happens on and what the exact error message is. Exact wording of the error is important.
2) The steps to reproduce the issue. For the steps, just put in the steps that you take to create what is happening, so someone can reproduce the issue.
So, the steps would be something like:
- Check that the language of the site is English
- Create a new Lesson,
- Add a Question type page to the Lesson
- Add a question of a certain type
- Add answers of a certain type and save it.
- Preview or log in as student and type the Lesson and enter in - see the results
- Switch the course language to one which users commas as decimal seperator
- Test again as student and enter a comma and see the error
3) State what you expect to happen. In this case, the expected behavior is that when the course language uses a comma as a decimal separator, then it should function normally and not give an error.
That's all there is to any good ticker. The steps are key. Someone on the dev team must be able to reproduce this problem using your steps. If they can't, they will not start working on it right away (or maybe ever).