The choice activity has an option to "Include responses from inactive/suspended users". There is unexpected behaviour if this is set to no, there are limits and inactive/suspended users have made a choice.

Testing:

1. Enrol 3 users in a course
2. Create a choice activity
3. Set "Limit the number of responses allowed" to Yes
4. Add an option and set the limit to 2
5. Set "Include responses from inactive/suspended users" to No
6. As two of the users select option 1
7. Change the course enrolment status for one of these users to inactive
8. As the third user navigate to the choice activity
   Notice the checkbox for option 1 is available. If "Include responses from inactive/suspended users" was set to Yes it would be greyed out and would have "(Full)" displaying after the Option name
9. Select Option 1 and hit "Save my choice"
   The user is now presented with "One or more of the option you have selected have already been filled. Your response has not been save. Please make another selection"

I'm not sure what the desired behaviour is, but I don't think it should be this. It could be:
1. Display "(Full)" after the option name as it does when "Include responses from inactive/suspended users" is set to Yes, or
2. Ignore inactive users in the limit and allow the user to make a selection if the number of active users that have made a selection is under the limit.

The way that the tool is usually used at our institution, 2 would be the better solution for us.

When inactive users are excluded it is very difficult to see what is going on with the limits. If at leats the teachers view showed the inactive users greyed out that could be helpful.

I'm seeing this issue in our 3.5.7 and in https://qa.moodle.net/ which is currently 3.8 dev.