Reset of project category when project admin changes avatar

When a project administrator (not JIRA administrator) changes a project avatar it resets the project category. The project category field is read-only, so there is no workaround by f.e. setting the project category manually.

Steps to reproduce:

• Login as a project administrator (role administrator for a project)
• Go to project
• Click project settings
• Click details
• Select different avatar
• Save

Expected result:

• Project category is still the same

Actual result:

• Project category is "none"

JIRA version is 7.2.5