JQL Query string length limited in Jira 6.0.2

The JQL Query length in the Issue Navigator has been limited in Jira 6.0.2 to about 2000 characters - roughly as long as can be accommodated when the Navigator's context is specified using the GET method - with the query encoded in the url. Indeed, executing the search specified in:

 issuekey in (DS-1984, DS-1985) 

... results in the page invoked through https://.../jira/issues/?filter=-2&jql=issuekey%20in%20(DS-1984%2C%20DS-1985)

A common use case where this is limiting is when specifying an itemized set of issues using the issuekey in () construct, very convenient when the list of issues is coming from an external source (external tool, spreadsheet, etc.). With four character project keys and four digit numbers, this amounts to about 200 issues, which is not unreasonable.

The syntax worked for much longer strings in Jira 5.0.1, presumably when the context of the query was passed using the POST method (we never had the need to closely inspect how it worked).

Currently, it is impossible to launch the Issue Navigator using the issuekey in () syntax with more than 200 issue keys even from an external tool and using the POST method, as the Issue Navigator's UI just shuts it off. This is rendering a number of established tools and processes inoperable.

Alternative ways of describing the selection, e.g. using filters, is not a viable option because the set of issues is generally composed by methods external to Jira and thus the only straightforward way is to use an explicit listing.