Double chest half to one single chest but can see the hitbox

Two double chests of mine have halved to single chests, although I can still see the hitbox for the right hand side of those chests.

I have been to the nether and back but this still hasn't fixed the problem.

When I attempt to access the "invisible" half of the chests, I get a server crash:

Version: 1.16.100.4
OS: Windows
Server start: 2020-11-26 17:37:18 GMT Standard Time
Dmp timestamp: 2020-11-26 17:39:25 GMT Standard Time
Upload Date: 2020-11-26 17:39:25 GMT Standard Time
Session ID: 1e4920ad-5aed-467c-8890-74f785f7166d
Commit hash: 1136cf3cc50c1cd8e89c3b1553d1d0708e61f1e0
Build id: 4919786
CrashReporter Key: 36a5dae5-c9c6-39a7-9d5e-280adfc92ccc

Crash
[INFO] 	at void CraftingContainer::serverInitItemStackIds[int,int,class std::function<void >] (UnknownFile:?)
	at void ChestBlockActor::serverInitItemStackIds[int,int,class std::function<void >] (UnknownFile:?)
	at void ContainerManagerModel::serverInitItemStackIds[void] (UnknownFile:?)
	at class InventoryContentPacket InventoryContentPacket::fromPlayerInventoryId[enum ContainerID,class Player &] (UnknownFile:?)
	at enum EventResult VanillaServerGameplayEventListener::onPlayerOpenContainer[class Player &,enum ContainerType,class BlockPos const &,struct ActorUniqueID] (UnknownFile:?)
	at void ServerInstanceEventCoordinator::sendServerLevelInitialized[class ServerInstance &,class Level &] (UnknownFile:?)
	at void EventCoordinator<class ActorEventListener>::processEvent[class std::function<enum EventResult >] (UnknownFile:?)
	at bool ChestBlock::use[class Player &,class BlockPos const &,unsigned char]const  (UnknownFile:?)
	at bool Block::use[class Player &,class BlockPos const &,unsigned char]const  (UnknownFile:?)
	at bool GameMode::useItemOn[class ItemStack &,class BlockPos const &,unsigned char,class Vec3 const &,class Block const *] (UnknownFile:?)
	at enum InventoryTransactionError ItemUseInventoryTransaction::handle[class Player &,bool]const  (UnknownFile:?)
	at void Container::createTransactionContext[class std::function<void >,class std::function<void >] (UnknownFile:?)
	at void PlayerInventory::createTransactionContext[class std::function<void >,class std::function<void >] (UnknownFile:?)
	at enum InventoryTransactionError ItemUseInventoryTransaction::handle[class Player &,bool]const  (UnknownFile:?)
	at void ServerNetworkHandler::handle[class NetworkIdentifier const &,class InventoryTransactionPacket const &] (UnknownFile:?)
	at bool NetworkHandler::_sortAndPacketizeEvents[class NetworkHandler::Connection &,class std::chrono::time_point<struct std::chrono::steady_clock,class std::chrono::duration<__int64,struct std::ratio<1,1000000000> > >] (UnknownFile:?)
	at void NetworkHandler::runEvents[bool] (UnknownFile:?)
	at void NetworkHandler::runEvents[bool] (UnknownFile:?)
	at bool Minecraft::update[void] (UnknownFile:?)
	at void ServerInstance::_update[void] (UnknownFile:?)
	at void ServerInstance::startServerThread[void] (UnknownFile:?)
	at class WhitelistEntry * std::_Uninitialized_move<class WhitelistEntry *,class WhitelistEntry *,class std::allocator<class WhitelistEntry> >[class WhitelistEntry * const,class WhitelistEntry * const,class WhitelistEntry *,class std::allocator<class WhitelistEntry> &] (UnknownFile:?)
	at unsigned int std::_Pad::_Call_func[void *] (UnknownFile:?)
	at configthreadlocale (UnknownFile:?)
	at BaseThreadInitThunk (UnknownFile:?)
	at RtlUserThreadStart (UnknownFile:?)