This is known problem with error reporting in code that downloads updater configuration scripts. There should have been error reported but to assemble it a wrong method was called. This is the result. ("It is not allowed to call path on scheme https)
Issue is here https://gitlab.labs.nic.cz/turris/updater/updater/issues/293
This is already fixed but not yet released as it is part of significant updater rewrite that should land in Turris OS 5.1 (not yet present in either branch).