I tried to use input_select.set_options to set new value for the entity.
It actually successful change the options.
Just when you open the entity and click SETTINGS it remains the value when you create or change in GUI.
Above is for duplicating the issue.
The real situation is under following log
Logger: homeassistant.components.input_select
Source: components/input_select/init.py:365
Integration: Input select (documentation, issues)
First occurred: 02:09:57 (5 occurrences)
Last logged: 02:30:04
Current option: test no longer valid (possible options: loves_me_not.mp3, Jingle_Bells.mp3, xxx)
Current option: loves_me_not.mp3 no longer valid (possible options: bb)
Current option: bb no longer valid (possible options: Item A, Item B, Item C)
Current option: Item A no longer valid (possible options: loves_me_not.mp3, Jingle_Bells.mp3,xxx)
Current option: loves_me_not.mp3 no longer valid (possible options: Item A, Item B, Item C)