The bottle was too big
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How it happens
A maker finds the hazmat figure, which is 500 mL per container, builds a generous travel bottle to it, and sells it as cabin-friendly. The security screening limit is far smaller and it is the one at the checkpoint.
Or the opposite
A maker designs to the small security figure and then describes the bottle as meeting federal requirements generally, which is true of one rule and not a complete statement. Being precise about which rule is part of the claim.
Capacity, not contents, is what is measured
The hazmat limit is on the capacity of each container, and screening looks at the container as well. A part-filled large bottle is a large bottle for both purposes.
Checked baggage is genuinely different
The hazmat exception covers carry-on and checked baggage, while the liquids screening restriction applies at the passenger checkpoint. A larger size has a legitimate market for checked bags and should be described that way.
So sell the size for the use
A carry-on range well under the screening figure, and a larger one described for checked baggage or for home refilling. Two honest products, rather than one with an ambiguous claim.
Do not print the security number on the bottle
It is set by TSA and changes without a rulemaking, and a molded or printed figure outlives the rule. Describing a bottle by its actual capacity is accurate for as long as the bottle exists.
Our shelf is already on the right side
It tops out at 120 mL and 127 of the 203 containers are at or under 100 mL, so building a compliant carry-on range from it is straightforward. The mistake is reachable only by going outside this shelf.