boost Not working when searching for a Synonym

[smyadam]

We are facing an issue where boost is not getting triggered if we are search for a word which is present in Synonyms list. We are using Solr 7.2.1
Below is our Configuration :

<lst name="defaults">
<str name="echoParams">explicit</str>
<int name="rows">10</int>
<str name="defType">synonym_edismax</str>
<str name="synonyms">true</str>
<str name="synonyms.analyzer">enAnalyzer</str>
<str name="synonyms.originalBoost">2</str>
<str name="synonyms.synonymBoost">1.99</str>
<str name="synonyms.constructPhrases">true</str>
.....
<str name="boost">vintage_date</str> ->  this boost is not applied if I search for a synonym.