Frosted Ice melts in the End due to skylight

Place a water source in the End

Place a Player or Armor Stand wearing Frost Walker boots near the water source to form Frosted Ice

The Frosted Ice should stay frozen like in previous versions

Instead, the Frosted Ice melts due to the addition of skylight in the End

In snapshot 25w33a, skylight was introduced to the end as a means of enabling the End Flashes feature. One probably unintended effect of this is that Frosted Ice now melts in the end, even though there’s no actual light source in the End.

Machines to make Frosted ice highways in the End have been possible for many years and this change breaks them, and breaks any existing Frosted Ice highway infrastructure in players' End dimensions.