The spatial predicate "IsDisjointTo" is almost the same as the inverse of "Intersects", except that it shouldn't match documents without spatial data. In another sense it's as if the query shape were inverted.
DisjointSpatialFilter is a utility filter that works (or worked, rather) by using the FieldCache to see which documents have spatial data (getDocsWithField()). Calculating that was probably very slow but it was at least cacheable. Since
LUCENE-5666 (v5/trunk only), Rob replaced this to use DocValues. However for some SpatialStrategies (PrefixTree based) it wouldn't make any sense to use DocValues just so that at search time you could call getDocsWithField() when there's no other need for the un-inversion (e.g. no need to lookup terms by document).
Perhaps an immediate fix is simply to revert the change made to DisjointSpatialFilter so that it uses the FieldCache again, if that works (though it's not public?). But stepping back a bit, this DisjointSpatialFilter is really something unfortunate that doesn't work as well as it could because it's not at the level of Solr or ES – that is, there's no access to a filter-cache. So I propose I simply remove it, and if a user wants to do this for real, they should index a boolean field marking wether there's spatial data and then combine that with a NOT and Intersects, in a straight-forward way.
Alternatively, some sort of inverting query shape could be developed, although it wouldn't work with the SpatialPrefixTree technique because there is no edge distinction – the edge matches normally and notwithstanding changes to RPT algorithms it would also match the edge of an inverted shape.