the Full Text Index Refresh task is for enabling search of roles, enittlements in the request access menu.
any changes in roles and entitlements such as: create new items, update display names or descriptions require to re run the full text index refresh task.
more to that , in debug there is object BundleManagedAttribute under type FullTextIndex which enable you to:
1. add speical chars for search such " , this is done by adding
<entry key="analyzerConfig">
<value>
<Map>
<entry key="delimiters">
<value>
<List>
<String>-</String>
<String>_</String>
</List>
</value>
</entry>
</Map>
</value>
</entry>
2. if you add searchable extended attributes to Roles / Entitlement you need to add them to BundleManagedAttribute to be searchable correctly in the request access menu.
for example:
if you added department attribue to Roles then add to <entry key="fields"> following line:
<FullTextField indexed="true" name="department"/>
for more details :
see https://community.sailpoint.com/t5/IdentityIQ-Wiki/Full-text-index-custom-delimiters/ta-p/214114 for more details.