1. Steps to reproduce.

Cast the card Thought Partition, targeting your opponent.

Choose any card in their hand that they have a single copy of. (At least, those are the circumstances under which I encountered the issue). The card's cost is correctly changed to {5} and the color is correctly changed to white. At this stage, the displayed information about the opponent's hand is as expected.

Wait for them to draw a SECOND COPY of the chosen card. (At least, that's how I encountered the issue).

The opponent casts the second copy of the chosen card, paying its unmodified cost.

At this point, the displayed information becomes inaccurate. If I recall, though I failed to take a screenshot, the first modified copy stops being displayed, despite not having been cast.

This makes it appear as though the opponent was wrongly able to ignore the modified cost, and cast the card for the original cost, which could infuriate the player. It also stops displaying known unambiguous information: that the opponent's hand contains a modified copy of the card, whose cost is now {5}.

1. -

2. Platform: PC.

3. Actual experienced results: the information known about the opponent's hand is no longer fully displayed after they cast the second (unmodified) copy of the chosen card.

4. Expected results: After the second (unmodified) copy of the chosen card has been cast, the opposing hand should still show a face-up copy of the first, modified card, with a cost of {5}. That is known information in all cases where the chosen card is not mono-white, and also in all cases where the chosen card's cost could not be payed with 5 mana.

5. Failed to take a screenshot, apologies. I did encounter the issue multiple times though, I'm confident I identified that something is off with Thought Partition information display and multiple copies of cards. I also confirmed that the first, modified card was still in hand (saw their hand by casting another Thought Partition later).

6. No workaround found for display issue. Gameplay-wise, if you're aware of the issue, you can simply use your memory. Annoyingly, the display makes things appear as if the cost modification of Thought Partition was bugged and non-functional, which is not the case, it's stricly a display problem.