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
@sva2 - This is expected as the story information is automatically written to the item each time the story is published. If you have a need to have the item details differ from the story details the item details will need to be manually updated after publishing an update to the story.
In the ArcGIS Online version of ArcGIS StoryMaps, there is a checkbox in the Publish options that lets you unhook this connection to the item details. This feature will be available in Enterprise 11.1.