The bug

The item lore of an item with attribute modifier doesn't differentiate between 2 of the 3 operations, the operations both show as +X%

Steps to reproduce

1. Place a command block with the command

   /give @p stick{AttributeModifiers:[{AttributeName:"minecraft:generic.movement_speed",Name:"test",Amount:0.5d,Operation:0,UUID:[I;1,1,1,1],Slot:"mainhand"},{AttributeName:"minecraft:generic.movement_speed",Name:"test",Amount:0.5d,Operation:1,UUID:[I;1,1,1,2],Slot:"mainhand"},{AttributeName:"minecraft:generic.movement_speed",Name:"test",Amount:0.5d,Operation:2,UUID:[I;1,1,1,3],Slot:"mainhand"}]}

2. Trigger the command block
3. Observe the item lore

Actual result

+0.5 Speed
+50% Speed
+50% Speed

Expected result

Each line is different, for example

+0.5 Speed
+50% Base Speed
+50% Speed