Day's Undoing only triggers one draw instead of seven, for example, Chasm Skulker only gains one +1/+1 and Ominous Seas only gains one foreshadow counter.

I have Jegantha in my sideboard as my commander for a deck which does not meet the companion requirements. I don't want Jegantha as my companion though, I want it as my commander and it won't let me use it that way since it's in the sideboard it automatically tries to use it as a companion.

Ceta Sanctuary does not recognize second state

Raka Santuary does not recognize when you control a blue permanent and a white permanent.

Jace, Telepath unbound not able to target cards in graveyard

When using Slimy Kavu, it turned my Opponents land into an island, not a swamp

On MTGO online, there are cards that are not working in standard. Narset's Reversal, Lutri the Spellchaser, and Expansion. I play an instant or sorcery but it's not letting me copy the spell. It only let's me copy if an ability triggers first then i can add it to the stack. But it should let me copy it right after I cast the spell. Please fix these issues as these cards are worth playing in tournament. I've tested it time and time again. Please respond back when you have time.

I played Lynx and it wouldn't let me tap a creature

The card Breaching Leviathan does not work properly on MTGO. I have cast it twice now and both times it has not worked as written.

1. Cast Breaching Leviathan
2. All nonblue creatures become tapped and DO NOT untap during their next untap step.
3. Actual: Nonblue creatures tapped with Breaching Leviathan DO untap during their next untap step.
4. Expected: Nonblue creatures tapped with Breaching Leviathan DO NOT untap during their next untap step.

Koth +1 is automatically picking the summoning sick mountain

1. i used the U/B ability from Lochmere Serpent to get him back into my Hand
2. 1 turn later enemy played macabre mockery and targeted my Lochmere Serpent
3. lochmere was in my hand not on my graveyard

Had 2 corpsejack manaces in play, triggred a +1/ +1 evolve. Each corpsejack menace has an effetc to double +1/ +1 counters but only 2 counters were added not 4.
Previous Ruling:
17/11/2017 If you control two Corpsejack Menaces, the number of +1/+1 counters put on a creature is four times the original number. Three Corpsejack Menaces multiplies the original number by eight, and so on.

A player plays time twister with an underworld dreams and spiteful visions on the field. Duel caster mage was then cast to copy the time twister. The triggers from underworld dreams and spiteful visions go on the stack. However the game breaks and causes an infinite loop of the game replay instead of resolving the triggers

Words of Waste isn't triggering when I pay for 1 on my upkeep and not drawing for turn.

i tryed to play a leyline of the void on my upkeep then i clicked undo to cancel and reset the mana but the city of brass doesnt work and i couldnt play the leyline of the void making me lost the game

Soul Exchange did not grant +2/+2 counters.
1. Soul Exchange was cast exiling Basal Thrull targeting Mindstab Thrull.
2. Mindstab Thrull was brought back to the battlefield.
3. Actual: No +2/+2 counter was placed onto Mindstab Thrull, resulting in a 2/2.
4. Expected: Mindstab Thrull should have a +2/+2 counter on it resulting in a 4/4 Mindstab Thrull.

When a player is unable to submit their sideboard due, often giving an error message, and often for having having 14 or 16 cards in their constructed sideboard.

For when an issue occurs when going to or from sideboarding back to the duel scene.