interveinal at the bottom.. Fe, maybe? which wuld be odd and unlikely.
would need more info.. could be bad irrigation habits.
the location is weird. makes it look like it should be a mobile nutrient but they don't match those symptoms.
SO,
Check pH make sure it's not too acidic or akaline. If that's fine move on to eliminate other possibilities.
If you increased p/k lately, or any other drastic nute changes, i'd consider dropping back to the previous formula. even if the change was 2 weeks ago -- assuming it was a slow progression. if you've kept track of how you fed, it helps shed light on things.