When giving yourself the greatest band of mana with the /give command or with JEI, it gives you a band and additionally drops one on the ground. You cannot collect the band and reloging will not remove the item. When targeting the item using the /data get command it says that the item has a pickup delay of 32767. Thus, it can never be picked up.

Using:
Minecraft 1.16.5
Forge 36.1.32
MythicBotany-1.16.4-1.3.15
Botania-1.16.5-418