Do the Rastafarians that are Orthodox usually give up marijuana? (Sorry if that is a silly or offensive question. I don't know much about Rastafarians or marijuana. About 15 years ago I thought I talked to an evil spirit while I was under the influence of marijuana and other drugs that I can't remember. It scared me after I sobered-up, because it seemed like I came close to worshiping or praying to it. So that is the reason for my curiosity.)
It depends on the individual. The Church has always frowned upon the usage of Marijuana, but has wisely not made this issue a deal breaker in evangelizing Rastas. In Jamaica, some Rastas will smoke Ganja outside of the Church gates, but never within the Church property. Rastas who have entered into the Tewahedo Faith respect the Church and her Teachings, and do not elevate their individual customs above the Teachings and Traditions of the Church. In areas where the usage of Ganja is legal, a Priest may perhaps "allow" it, but I doubt if any Priest would give their blessing to the use of Ganja. From what I know, most Rastas who have converted to the Tewahedo Faith and continue to use Ganja do not ask their Priest about it, for they know that they will most likely be encouraged to stop.
For the record, I do not use marijuana, altghough I support its legalization. However, whether legal or illegal, I would encourage all people to follow the Teachings of the Church and the counsel of their Priests when considering its usage.