Log warning: invalid option for input_select, even though no invalid options has been selected

Hello everyone. I use a dropdown (input_select) as mode selector for my ventilation fan, but I keep getting this error in the log:

Logger: homeassistant.components.input_select
Source: components/input_select/__init__.py:303
Integration: Input select (documentation, issues)
First occurred: 21:24:08 (1 occurrences)
Last logged: 21:24:08

Invalid option: (possible options: Automatic, Manual, Maximum, Minimum)

I can’t understand why this error occurs. According to the log there hasn’t been selected any invalid option (it is just blank according to the error text above). The error keeps returning several times a day. I don’t use any automations to change the value of the input_select, it is all done manually by the HA user.

Previously I used a combination of UI and yaml-file to configure my helpers, but I tried to delete input_select.yaml and configure everything from the UI, but this did not solve the issue.

Any ideas?

See here: Sporadic warnings in log referencing invalid input_selection options. · Issue #11991 · home-assistant/frontend · GitHub