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.

i cast a spell with Hullbreaker horror. its effect riggered and then didn't allow me to use it's ability to target anything.

The Reality Chip was attached to a creature. After the equipped creature died The Reality Chip did not return to be a creature. Note that I had a Hammer in hand and could not use it to equip The Reality Chip, because it was not a creature.

When I play the long reach of night card, during 2 turns opponent does not discard a card

1. I played Doomsday.
2. Resolved Doomsday and chose 5 cards from my library and graveyard.
3. Opened Temporary Zone Window, i executed Undo.
4. Magic Online rolled back and couldn't progress the game.

Sorry if this doesn't go in this category - I was trying out the Esper Greasefang deck in Pioneer this evening and while I was able to reanimate Parhelion II it never showed/let me crew it... is it bugged?

Magma Opus deals huge damage to any permanent you trying to tap.
19:39: AJImpy casts Magma Opus targeting Gifted Aetherborn for 4, Hallowed Fountain for 33, and Sanctum Seeker.
19:41: AJImpy casts Magma Opus targeting Henrika Domnathi for 4, Radiant Destiny for 81, and Raugrin Triome.
Sanctum Seeker was destroyed as well.

11/18 Update or Install Error after Downtime

Reidane, God of the Worthy did not properly tax March of Otherworldly light. Steps are

1. Cast March of Otherworldly Light targeting Reidane, God of the Worthy so X = 3
2. There is a Paladin Class also taxing March
3. Actual: It cost 5 mana to cast the spell
4. Expected: It should cost 7 due to the Tax effect of Reidane and Paladin Class

I cast Kotose, the Silent Spider choosing to exile Kumano Faces Kakkazan.
I play Kumano Faces Kakkazan.
When the 3rd lore counter is put on it, the saga is supposed to be exiled and returned to the battlefield transformed as Etching of Kumano under my control. However, it went to my opponent's control.

Target opponents woe strider with play with fire
Opponent sacrifices the goat in response
Ability resolves
Opponent sacrifices woe strider in response

Abandoned Sarcophagus exiles cards when you cycle them, instead of letting them go to the yard. It specifically says they go to the yard if cycled.

POST 11/10/21 Downtime mid game restart

Since last downtime Pauper no longer has a 2 player Queue,
why?

Hey there,

I report a bug that occurs in my Pioneer open constructed games.

Dread Presence's trigger doesn't work well. It seems like it works like a "hasn't been choose" choice mode.
I mean when Dread is in play, the first swamp let me choose one of the two options, the second swamp triggers automatically the option that hasn't been choosen yet, and from the third swamp no trigger happens anymore.
This is a bug that happens since 2 or 3 days consistently.
Thank you in advance.

Situation
1.I have Wiretapping on my field
2.End step of my opponent, I activate Demon's Due
3. Actual : After it resolves, Wiretapping forcedly activates, and the mandatory trigger forces me to draw my whole deck
4. Expected : Wiretapping is only supposed to trigger once, and only during my draw step

The card was Life of Toshiro Umezawa. The Black Saga for 2 Mana. I couldn't click the same Mode again.

Any time Faithbound Judge or Sinner's Judgment triggers, the game gives an error message and crashes. This immediately makes it impossible to continue playing the match, and seems to consistently occur every time the trigger resolves.