[unsolved-fix,too trouble]Mesmeric Sliver fateseal mandatory

[Nexhro]

Describe the Bug:
Mesmeric Sliver's ETB ability will always prompt popup showing the top card of AI's library, asking whether to put the shown card on teh bottom of AI's library.

Which card did behave improperly ?
Mesmeric Sliver

Which update are you using?(date,name)Which type(Duel,Gauntlet,Sealed Deck)
JOU, duel

What exactly should be the correct behavior/interaction ?
The fateseal is optional.

Are any other cards possibly affected by this bug ?
-

[Gargaroz]

Well, it's harmless and will be hard to fix with a legacy card, so I'll leave it as it is.