It has to survive the contents
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The requirement, in its own words
Special packaging must continue to function with the effectiveness specifications set out in the standard when in actual contact with the substance contained in it, and it must continue to do so for the number of openings and closings customary for its size and contents.
That is a chemical compatibility clause
It is sitting inside a child-safety standard, and it is the clause this product category runs into hardest. Essential oils plasticize, soften and craze a lot of polymers, and a closure that has gone soft no longer resists anything.
The rule even tells you how to satisfy it
By appropriate scientific evaluation of the compatibility of the substance with the packaging, and by technical evaluation of wear, stress and activation force over normal use. In plain terms: test it filled, and test it after months rather than after an afternoon.
The effectiveness numbers it has to hold
Not less than 85 percent child-resistant effectiveness without a demonstration, and not less than 80 percent after a demonstration of the proper means of opening. Those are the figures the package must still meet once your oil has been sitting in it.
Two more clauses worth knowing
Special packaging under these paragraphs shall not be reused, which matters if you were planning a returnable bottle. And restricted-flow packaging must release no more than 2 milliliters per activation, which is a design constraint on a dropper, not a labeling one.
Keep a filled unit and come back to it
Filled, capped, labeled and opened occasionally over six months. It is the only evidence that speaks to the clause as written, and it costs one bottle.
This is where supplier paperwork stops helping
A datasheet describes a closure as supplied, usually tested dry or against a reference liquid. The standard asks about your substance in your package over your use pattern, which is a question only your own retained samples can answer.