Error:
Schedule of DISABLED configuration triggers build when Run Mode is inherited from DISABLED configuration

Steps
root`s "Run mode" is "Sequential" for example
Create child configuration (for the "root" in my case) with Run mode "Inherited..."
Set schedule: "Periodical" or "Cron"
Set up configuration as you need
Wait until schedule triggers build

Then change Run Mode of PARENT config ("root" in this case) to "Disabled"
Wait until schedule triggers build

Expected:
Schedule of DISABLED configuration does NOT trigger build even Run Mode is inherited from DISABLED configuration

See notes under Schedule settings
>>Please note that if the configuration is not runnable, the schedule will not take effect (but is able to be inherited by child configurations).

Nota bene
But schedule DOES NOT trigger build (as expected) when Run Mode is set to DISABLED for the child configuration (overridden parent`s Run Mode)