Within the storage-parameters.config.cfg file under $FGL_HOME\config the word OVERFLOW should only be on the aggregate-iot & scalar-iot entries.
"obs_metric_aggregate" : "${tablespace.clause} PCTFREE 0 STORAGE (NEXT 10M MAXEXTENTS UNLIMITED)",
"obs_metric_scalar" : "${tablespace.clause} PCTFREE 0 STORAGE (NEXT 10M MAXEXTENTS UNLIMITED)",
"obs_string" : "${tablespace.clause} PCTFREE 0 STORAGE (NEXT 10M MAXEXTENTS UNLIMITED)",
"obs_binary" : "${tablespace.clause} PCTFREE 0 STORAGE (NEXT 10M MAXEXTENTS UNLIMITED)",
"obs_metric_aggregate-iot" : "ORGANIZATION INDEX COMPRESS 2 ${tablespace.clause} PCTFREE 0 STORAGE (NEXT 10M MAXEXTENTS UNLIMITED) OVERFLOW ";
"obs_metric_scalar-iot" : "ORGANIZATION INDEX COMPRESS 2 ${tablespace.clause} PCTFREE 0 STORAGE (NEXT 10M MAXEXTENTS UNLIMITED) OVERFLOW";