Steps to reproduce:

1. Create a user profile field of type 'checkbox' and name Test field.
2. In a course create an activity, with restriction related to that profile field. E.g. that Test field is equal to 1 (or not, or 0 instead of 1).

Expected result: it works.

Actual result: it does not.

The problem is around here: https://github.com/moodle/moodle/blob/master/availability/condition/profile/classes/condition.php#L297

It is using ===. However, while the value of the profile field for the user is a string (See cast above the switch) the test value in the JSON for this rule is an int, so this is always false.