At the moment to solve these black screens is to have a contracted subscription and not to share it in multics because if you share it they will screw it up and you will have a black screen whenever movistra wants. The multics configurations and versions can do little here I think.
cards owners saying it works fine without any issue at all on oscam the situation affect only multics users for example, M. SERIES 2 HD now working for like 10 minutes, and it goes black for 10 minutes and keep going like this i've tried to look into it but i didn't find anything that helps identifying the whole issue with movistar
Those who have black screen is because some cards are marked and give black screen in the oscam log it appears OK but the screen is black. This is not a problem with multics or oscam as the marked cards do not work on the Movistar iplus either.
This is a problem that can only be solved by oscam and only by someone who has the real card My opinion is that it should be tested by elimination and with small steps But this is not easy and requires a lot of testing