When you use /replaceitem entity @s armor.(head,chest,legs,feet) <armor item> on a player that is viewing an external ui such as a villager trade interface, chest, etc., replacing the item does not work. I am assuming this is because when an interface is open the slots that can be replaced with /replaceitem change.
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alright thank you
Thank you for your report!
However, we are already tracking this issue, and this report is a Duplicate of MC-87019, which is a report that has not been resolved yet.
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