What are these white granules at the leaf-ends of my gold fruit palm?

Question

I have had a gold fruit palm in my apartment for over a year now, and it has always been happy and healthy. Recently I have begun fertilising it once a week or so with a (German) liquid palm fertiliser, carefully following the instructions.

A week or so after I started (give or take), white granules appeared at the tips of most of the leaves (see photos). When I brush it off, it feels like salt (i.e., like tiny crystals).

Does anyone know:

1. What it is?
2. What is causing it?

Is it possible to over-fertilising a potted house palm? Attempting to translate, the ingredients of the fertiliser are:

• 2.6% Nitrate
• 2.6% Ammonium
• 1.8% Carbamide/urea (CO(NH₂)₂)
• 3.0% Phosphate (P₂O₅)
• 5.0% K₂O