When sideboarding in Explorer Ranked BO3 with the deck below (Windows), I can interact with my deck and sideboard but when I hit submit, I am briefly taken to the waiting screen, and then returned to the sideboarding screen. At that point my sideboard is not visible, and I cannot interact with my deck or hit submit again. When I enter into the next round of the match, my sideboarding has not been submitted. This does not appear to happen with other decks, only this one:

Companion
1 Jegantha, the Wellspring (IKO) 222

Deck
4 Fable of the Mirror-Breaker (NEO) 141
4 Scavenger's Talent (BLB) 111
4 Mayhem Devil (WAR) 204
4 A-Cauldron Familiar (ELD) 81
4 Bloodtithe Harvester (VOW) 232
4 Witch's Oven (ELD) 237
4 Deadly Dispute (AFR) 94
4 Blightstep Pathway (KHM) 252
1 Mountain (MIR) 346
1 Castle Locthwain (ELD) 241
4 Overgrown Tomb (GRN) 253
2 Swamp (MIR) 340
4 Blood Crypt (RNA) 245
3 Ygra, Eater of All (BLB) 241
4 Fatal Push (KLR) 84
3 Thoughtseize (AKR) 127
2 Sulfurous Springs (DMU) 256
4 Blackcleave Cliffs (ONE) 248

Sideboard
4 Leyline of the Void (M20) 107
1 Jegantha, the Wellspring (IKO) 222
1 Furnace Reins (MOM) 141
1 A-The Meathook Massacre (MID) 112
1 A-The Meathook Massacre (MID) 112
2 Abrade (AKR) 136
1 Thoughtseize (AKR) 127
4 Damping Sphere (DAR) 213