What's happening
The workaround suggested to search for Customer Request types stopped working.
In earlier versions of JIRA Service Desk (2.4-OD-04) users could use the following syntax when searching for Customer Request Types using JQL:

"Customer Request Type" = "<projectKey>/<request-type>"

I worked just fine and sometimes all the user needed to do was to look directly in the database the correct values for the <request-typ> when the usual values didn't match.
However, since 2.5.1-OD-03-002, it stopped working.

Expected behaviour
Searching for Customer Request Type should be possible using the correct syntax:

"Customer Request Type" = "<projectKey>/<request-type>"

Actual Behaviour
It's not possible anymore to search request types even if the values for the <request-type> constraint match the database key values.