PaperMC/paper-server/nms-patches/net/minecraft/world/level/block/BlockJukeBox.patch

--- a/net/minecraft/world/level/block/BlockJukeBox.java
+++ b/net/minecraft/world/level/block/BlockJukeBox.java
@@ -62,7 +62,13 @@
         TileEntity tileentity = generatoraccess.getBlockEntity(blockposition);
 
         if (tileentity instanceof TileEntityJukeBox) {
-            ((TileEntityJukeBox) tileentity).setRecord(itemstack.copy());
+            // CraftBukkit start - There can only be one
+            itemstack = itemstack.copy();
+            if (!itemstack.isEmpty()) {
+                itemstack.setCount(1);
+            }
+            ((TileEntityJukeBox) tileentity).setRecord(itemstack);
+            // CraftBukkit end
             generatoraccess.setBlock(blockposition, (IBlockData) iblockdata.setValue(BlockJukeBox.HAS_RECORD, true), 2);
             generatoraccess.gameEvent(GameEvent.BLOCK_CHANGE, blockposition, GameEvent.a.of(entity, iblockdata));
         }