i know this is a little but still needs be pointed out for others with the same question. as you can see in this picture, one happy ghast has a harness around its bottom, and one other has none. to recreate this is just with certain mobs it won't work with like horses is one it will work with, sheep it will not.
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Thank you for your report!
However, this issue is Working As Intended.
The behavior you have reported is working as intended: Please refer to the 25w16a changelog, which is quoted below.
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