Unable to Find Project when Project Key have a Number

Unable to Find Project when Project Key is using Number

Steps to Reproduce:

1. go to Administration > System > General Configuration and click on Advance Settings.
2. change jira.projectkey.pattern to:

    ([A-Z][A-Z0-9]+) 

3. Create a new service desk project in Service Desk > Create a Service Desk.
4. set the project name and project key to R2D2.
5. click the 'Cutomer Portal' tab, then click on 'View the Customer Portal'.
6. log out from service desk, it will still on the Customer Portal Login page.
7. copy the URL of the page. For example:

    http://localhost:8625/servicedesk/customer/r2d2/user/login?destination=r2d2 

8. open a new browser window/tab and paste the URL.

Expected Results:
The R2D2 Service Desk Customer Portal login page will appears.

Actual Results:
The following message appears in the page:

 The Service Desk you are trying to view does not exist. 

Notes:

• After the URL being paste and go, the URL changes to:

   http://localhost:8625/servicedesk/customer/r/user/login?destination=r2d2%2Fuser%2Flogin 

• Using another way of entering the customer portal URL like below, will throw the same message.

   http://localhost:8625/servicedesk/customer/r2d2 

• As based on this documentation, R2D2 is supported.