During Pack 2, Pick 3 of a DMU QD.
I have 6 cards in my Sideboard, the UI layout is with the default with the drafted cards on the bottom.

Could not move the bottom-most card (6th card out of 6), the "Djinn of the Fountain", to my Deck. What this means specifically is:
- Mousing over the Djinn of the Fountain doesn't highlight the card
- Clicking the Djinn of the Fountain doesn't move the card to my Deck.

Workarounds:
Taking additional cards out of my sideboard (until it is < 6).
Switch the layout to the vertical split.
Scrolling the sideboard down (unnecessarily).

Adding additional cards to my sideboard triggers this behavior for any card > 6.

Using untapped.gg overlay.