The bug:

In snapshot 25w41a, skeleton horses were changed to be sunburned. However, unlike zombie horses, they cannot be protected from sunlight with horse armor, as zombie horses can.

This bug causes players' tamed skeleton horses to die when exposed to the sun while in 25w41a.

Steps to reproduce the issue:

1. Be on an older version.

2. Create/enter a world with Creative mode enabled, or enter a Survival world if you have tamed skeleton horses.

3. If you are in Creative mode and don't have a skeleton horse, run the following command:

   /summon skeleton_horse ~ ~ ~ {Type:4,Tame:1,}

4. Mount it with a saddle if it is not already mounted.

5. Update to snapshot 25w41a.

6. Enter the world where the steps were taken.

Actual result:

Skeleton horses begin to burn and die from the sun.

Expected result:

Skeleton horses should be fitted with horse armor to protect them from sunlight, just like zombie horses.