Rancher Support is per schedule posted in the terms of service page on rancher.com. Also, shared in the FAQs under these two questions:
Does Rancher not offer support in my own timezone? Is the SLA response times for all responses or just the initial response?
Currently, only tickets with a severity level of "Severity 1" are fielded on Saturdays and Sundays. For tickets of all other severity levels, Rancher Support follows the business week of Monday-Friday only.