SolrPlugin WebSearch filters not working

We have the SolrPlugin 7.30 installed on foswiki 2.1.6, using solr-5.5.5. Indexing and basic searching seems to work well. However, the "Filter results" options in the left-hand column don't seem to do anything.

For example, if I browse to WebSearch (or use the upper-right corner search box), I can enter search terms and everything works properly. However, if I select a "Web" or specific "Media" in the left-hand column, the search results don't change or update (even after clicking on Search again). The same thing happens if I check "In current web" below the search box. However, the "Exact search" checkbox does work.

When checking a filter or "In current web", the web console displays.

[Error] TypeError: undefined is not an object (evaluating 'e.val')
   getQueryValues (ajax-solr.js:1:13385)
   inQuery (ajax-solr.js:1:13562)
   isSelected (ajax-solr-widgets.js:1:641)
   checked (ajax-solr-widgets.js:1:3884)
   anonymous (Anonymous Script 1 (line 18))
   ge (jquery.render.js:1:8407)
   fe (jquery.render.js:1:7383)
   render (jquery.render.js:1:21074)
   _tag (jquery.render.js:1:17338)
   anonymous (Anonymous Script 2 (line 6))
   ge (jquery.render.js:1:8521)
   fe (jquery.render.js:1:7383)
   afterRequest (ajax-solr-widgets.js:1:3832)
   (anonymous function) (ajax-solr.js:1:1907)
   handleResponse (ajax-solr.js:1:7954)
   (anonymous function) (ajax-solr.js:1:15654)
   l (jquery-2.2.4.js:1:38323)
   fireWith (jquery-2.2.4.js:1:39082)
   r (jquery-2.2.4.js:1:74135)
   (anonymous function) (jquery-2.2.4.js:1:79977)

One more possible clue is that if I check "In current web", the left-hand filter options do update to remove "Web." However, the search results themselves never update no matter what I do.

Any suggestions or fixes would be greatly appreciated.

-- DevinBougie - 04 Feb 2020