Let me preface this by saying: I am unsure if this should be classified as a bug or go to feedback.
As a powdered snow cauldron puts you out of being on fire like water, a blaze in the stuff should also take the same damage as in water. That also goes for striders.
Thank you for your report!
We're tracking this issue in MC-205031, so this ticket is being resolved and linked as a duplicate.
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