Bloom, the white film
Updated
A tube that looked perfect in November has a dull white haze on it in January. The balm is fine and the product looks spoiled.
What you are seeing
Fat bloom: fat that melted, migrated to the surface and recrystallized there in a different, larger crystal form that scatters light.
It is the same phenomenon as the white on old chocolate, and it has the same cause and the same lack of consequence. The balm is not rancid, not contaminated and not unsafe.
Why it happens
Temperature cycling. Warm enough to soften, cool enough to set, repeatedly. A shipment in a hot van then a cold warehouse does it in two days.
Cocoa butter blooms most readily, then shea. A formula heavy in either is more prone.
Slow cooling at the pour also sets up larger crystals in the first place, which makes later bloom easier.
Fixing it
Cool the pour fast. A cold setting surface or a cool room, not a warm bench overnight.
Take the melt fully above the highest melting point in the formula so nothing is left seeded, then bring it down without dawdling.
Reduce the cocoa fraction, or move some of it to a butter with a narrower melting range.
And control storage and shipping, which is where most bloom is actually created rather than in your kitchen.
What to tell a customer
The truth, briefly: it is the fat recrystallizing after warmth, it is cosmetic, and rubbing it warms it straight back out.
What not to do is replace the tube silently and learn nothing. A cluster of bloom complaints from one region in one month is a shipping-lane problem and it is worth knowing.