The bug
When a soul speed enchanted book is dropped by bartering with piglins, it is labeled with a light blue instead of a yellow name. That's because the book doesn't use the StoredEnchantments but the Enchantments tag instead. This causes these books to be unable to be combined successfully in an anvil.
Linked issues
is duplicated by 8
MC-174519
Soul Speed Enchantment book cannot be applied
Resolved
MC-174534
Piglin Soul Speed Enchant Trade Bug
Resolved
MC-174555
Enchanted book with soul speed has yellow text in the combat tab/search items instead of aqua/light blue
Resolved
MC-174580
The enchantment book for Soul Speed 3 cannot be combined with any boots.
Resolved
MC-174656
Soul Speed Enchanted Book Title Has Wrong Color
Resolved
3 more links
Attachments
Comments 2
Sparkofphoenix also had this issue https://youtu.be/02O510KkaHg. Sorry that it is german. But here some more information.
He combined the Soul speed book with a mending book and then he combined it with boots and soul speed was not on the boots. But later he suddenly had soul before he wanted to do it in creative mode.
This is caused by the entry in the loot table being
enchanted_bookinstead ofbook, like all other loot tables that enchant books