Make of this what you wish: the FAA says, "Additional non-hazardous ice packs (blue ice, gel packs, etc.) can be used to supplement the dry ice. However, for carry-on baggage, if the product contains any liquid or gel in excess of 100 ml (3.4 oz) per container, the TSA security rules require that the product be in the frozen state (i.e., solid) when the passenger goes through security screening."
https://www.faa.gov/hazmat/packsafe/...nfo/?hazmat=11