It has happened to me twice already. I cast Thoughtseize, and it resolves. To be more accurate, the opponent's hand was shown but briefly disappeared before I could interact (choosing a card to be discarded and therefore continuing the game).
When this happened for the second time I noticed an additional pattern: the panel displaying the opponent's hand disappeared when I clicked one of the "zones" buttons to see cards I already knew about. Namely, on the first occurrence of the bug, I clicked on the Companion "heart icon" of the opponent during the Thoughtseize resolution. On the second occurrence, I clicked on the "eye icon" to check which cards from the opponent where already revealed and clean it up before finishing the Thoghtseize resolution - a pattern that's probably not unusual.
In both cases, the bug occurred when clicking one of those icons. The selected zone was displayed, but the opponent's hand disappeared. Since Thoughseize is not a "may" effect, I had to select a card from the opponent's hand to proceed (unless the hand was all lands), and therefore the game was "stuck" and I couldn't continue. Meanwhile, my clock was running, so I had to concede the game.
When this happened for the second time I noticed an additional pattern: the panel displaying the opponent's hand disappeared when I clicked one of the "zones" buttons to see cards I already knew about. Namely, on the first occurrence of the bug, I clicked on the Companion "heart icon" of the opponent during the Thoughtseize resolution. On the second occurrence, I clicked on the "eye icon" to check which cards from the opponent where already revealed and clean it up before finishing the Thoghtseize resolution - a pattern that's probably not unusual.
In both cases, the bug occurred when clicking one of those icons. The selected zone was displayed, but the opponent's hand disappeared. Since Thoughseize is not a "may" effect, I had to select a card from the opponent's hand to proceed (unless the hand was all lands), and therefore the game was "stuck" and I couldn't continue. Meanwhile, my clock was running, so I had to concede the game.
