Points to consider:

After e recent upgrade of GRC box many a times reporting functions does not fetch/display long text fields like reason code description while running Firefighter log summary report.

Checks: If all the other customizing sets are maintained and only such long text values are not populating.

do first: go to TABLE TTXOB and check whether Text object GRC is there(normally it is absent when this error comes).

second: check that TABLE TTXID has any entry for GRC (normally there exists 12 entry but ID LTXT is absent).

third: check table TTXID has any entry GRAC as Object and LTXT as ID.

if yes, then create an entry GRC as object and LTXT as ID in table TTXID first then enter Object in table TTXOB.

Test: Now if the report is run all the fields will be populated.

Explanation: To update the log firefighter uses GRC object and LTXT as id so to fetch the entries from STXH by

     Class CL_GRAC_LOG_REPORT , method GET_LOG_SUMMARY is triggered when we try to get the firefighter logs from PORTAL.  Inside that, when cl_grac_api_spm_audit_wf=>if_grac_api_spm_audit_wf~queryis called  decription failed as GRC is not maintained.

After the steps are followed desired output arrives.