This does seem like a bug, however the ranked reset is tomorrow, so I don't think our developers will be able to identify the issue by the time your rank is reset. If you complete your placement matches and the rank still isn't showing up, send me a PM and I can make a bug ticket for it.
There's a chance the ranked reset would solve the problem somehow, but even if it doesn't, at least then you'll have a consistent rank for the devs to test that isn't about to be reset.
There's a chance the ranked reset would solve the problem somehow, but even if it doesn't, at least then you'll have a consistent rank for the devs to test that isn't about to be reset.