Fateseal mechanic doesn't seem to be working

[theonetruenerd]

When using mesmeric sliver, the fateseal effect is offered, and if you click yes the window opens showing the top card of the opponent's library correctly, but there is no option to select the card to put on the bottom of the opponent's library or leave as is.

[jeffwadsworth]

[[Mesmeric Sliver]]

[github-actions]

Mesmeric Sliver - (Gatherer) (Scryfall) (EDHREC)

{3}{U}
Creature — Sliver
2/2
All Slivers have "When this permanent enters, you may fateseal 1." (To fateseal 1, its controller looks at the top card of an opponent's library, then they may put that card on the bottom of that library.)