This might be a Bug of Story Maps in ARCGIS Enterprise 10.9.1
When trying to change the Name (Title) of the Story Map at its ARCGIS Enterprise Item Page
It Initially will work BUT if you edit then Publish your Story Map. The Title of that you just changed in its ARCGIS Enterprise Item reverts back to the original Title.
We have all the Updates and Patches to our ARCGIS 10.9.1 Enterprise so we cannot explain why this only happens with Story Maps Items