Afghan

Hey everyone just noticed these dark spots couple of days ago.The plant is 3 weeks into flower.Any assistance with the problem please?My Ph is fine and its not heatstress.Possibly Mg defeciency?sorry bout the quality better pics coming tomorow.please view pic

https://www.rollitup.org/members/bosofying-albums-afghan-picture21419-cant-post-pics-thread-some.jpg