Multi Phrase Query does not find my documents - solr

Question

As part of an upgrade plan from version 6.2.1, I'm setting up a new Solr (7.6.0).
Surprisingly, one of our simple tests failed - inserting a document with some text and then trying to search for it.
The text that was inserted is:
I will think about it.
Request handler configuration:
<requestHandler name="/select" class="solr.SearchHandler">
<lst name="defaults">
<str name="echoParams">explicit</str>
<int name="rows">20</int>
<str name="df">text_en</str>
<str name="hl.fragsize">100000</str>
<str name="hl.maxAnalyzedChars">100000</str>
</lst>
</requestHandler>
This is how the field is configured:
<field name="text_en" type="text_en" indexed="true" stored="true" multiValued="true" />
<fieldType name="text_en" class="solr.TextField" positionIncrementGap="100">
<analyzer type="index">
<tokenizer class="solr.StandardTokenizerFactory"/>
<filter class="solr.LowerCaseFilterFactory"/>
<filter class="solr.CommonGramsFilterFactory" words="lang/stopwords_en.txt" ignoreCase="true"/>
<filter class="solr.StopFilterFactory" ignoreCase="true" words="lang/stopwords_en.txt"/>
<filter class="solr.EnglishPossessiveFilterFactory"/>
<filter class="solr.KeywordMarkerFilterFactory" protected="protwords.txt"/>
</analyzer>
<analyzer type="query">
<tokenizer class="solr.StandardTokenizerFactory"/>
<filter class="solr.SynonymFilterFactory" synonyms="synonyms.txt" ignoreCase="true" expand="true"/>
<filter class="solr.LowerCaseFilterFactory"/>
<filter class="solr.CommonGramsFilterFactory" words="lang/stopwords_en.txt" ignoreCase="true"/>
<filter class="solr.StopFilterFactory" ignoreCase="true" words="lang/stopwords_en.txt"/>
<filter class="solr.EnglishPossessiveFilterFactory"/>
<filter class="solr.KeywordMarkerFilterFactory" protected="protwords.txt"/>
</analyzer>
</fieldType>
"will" and "it" appears in stopwords_en.txt file.
According to Analysis in the Admin Web App, those are the final tokens that are inserted into the index:
text: i i_will will_think think about about_it
position: 1 1 2 3 4 4
Search for text_en:"I will think about it" doesn't find the document.
Strange thing is, the query "I will think think about it" does work...
Using debugQuery, I noticed a difference compared to our current version.
6.2.1 is using MultiPhraseQuery
7.6.0 is using SpanNearQuery
In version 6.2.1:
"rawquerystring":"text_en:\"I will think about it\"",
"querystring":"text_en:\"I will think about it\"",
"parsedquery":"MultiPhraseQuery(text_en:\"(i i_will) will_think think (about about_it)\")", ...
In 7.6.0 (btw, also in 7.5.0):
"rawquerystring":"text_en:\"I will think about it\"",
"querystring":"text_en:\"I will think about it\"",
"parsedquery":"SpanNearQuery(spanNear([spanOr([spanNear([text_en:i, text_en:will_think], 0, true), spanNear([text_en:i_will, text_en:think], 0, true)]), text_en:about_it], 0, true))", ...

Answer 1

I've found the culprit.
Sharing it to support future googlers.
There was a mistake in the field configuration in schema.xml file.
In the "query" analyzer, instead of "CommonGramsFilterFactory", it should be "CommonGramsQueryFilterFactory".