Yellow new leaf growth on Phrag.

[Jaxx10]

Hello, so I purchased a Phrag. Fritz Schomburg, it came with a basal growth that seems it's starting to yellow slightly but the original plant has a yellow leaf that is the last leaf that it grew (top leaf). Underneath I see some rust looking stuff on it and some brown tips as well. Is it a deficiency or a virus/fungus/bacterial disease.... What can I do to make sure it doesn't spread or fix it. I cleaned the leaves with alcohol in case it was mites or something and I put some cinnamon on the leaves.