Specific [Custom Setting] seems glitched, you can enable, disable but not read current state or toggle
Samsung Galaxy S20 FE 5G with (unrooted) Android 12 here.
My S20 has a feature called "Extra Dim" (to dim the display even more than the default minimum) which is identified by the Custom Setting "Find Setting" as (secure) "reduce_bright_colors_activated" with value 0 or 1.
I can ENABLE or DISABLE this specific setting without any problem using tasker, but surprisingly I cannot READ the current state, as Custom Setting doesn't return a value to the variable referred to by the "Read Setting To" setting (it returns the name of the variable, as usual when using uninitialized variables).
Furthermore while on finding this setting tasker informed me that it's possible to toggle the setting, the toggle doesn't work and throws an error msg in the error log, at a guess because it cannot toggle when it can't retrieve the actual state.
The peculiar thing is that the "find" mechanism on identifying the respective setting by manually changing the setting via android settings, is able to identify the name of the setting as well as the type of values it uses (0/ 1), so Tasker internally seems to be very well able to retrieve the values.
Btw: I do use Custom Settings for other settings like "Enhanced Processing" (Global sem_enhanced_cpu_responsiveness) and it works without any issues, I can ENABLE, DISABLE and READ current state just fine, so doesn't seem to be a general problem of Custom Settings.