In Minecraft 1.16.0.53 and 1.16.0.51 Whenever you use /enchant command to enchant any item it gives the enchantment but won't show the gradient visual (the glow visual that enchanted items got on them). but after you use it at least for once the visual comes back.
it won't affect survival cause you will never use /enchant. everything is ok with enchanting table but /enchant has this problem. check it out by yourself. use /enchant to enchant an item then you will see that the item won't glow but after you use to break something with it the glow shows up. Not very important ,but bug is bug and must be fixed.
I wonder why this happens they just added something to the game.it should not break other things I am a programmer i know java and c++ and I'm confused what are mojang staff doing there :|