Hello,
I'am using paper 1.16.3.
I've played one my server and one of my villagers randomly disappears.
Sorry for my english, its not my main language.
Thanks for help,
StudioCrusader

Here is result of /version in console:
[15:35:13 INFO]: This server is running Paper version git-Paper-253 (MC: 1.16.3) (Implementing API version 1.16.3-R0.1-SNAPSHOT)
[15:35:13 INFO]: You are running the latest version

Here is result of /plugins in console:
[15:36:02 INFO]: Plugins (63): AdvancedOreGen, AFKFishing, AFKPlus, AmkMcAuth, BentoBox, BetterDispensers, BetterSleeping3, ChatFilter, DeathCoordinates, DeathMessagesPrime, DiscordSRV, dynmap*, Emoji*, EmojiChat*, Essentials, EssentialsChat, Gaea, Geyser-Spigot, GoldenEnchants, HealthViewr, HolographicDisplays, InfoHUD, InventoryRollback, LaunchMultiCommands, LuckPerms, Multiverse-Core, Multiverse-Inventories, Multiverse-NetherPortals, Multiverse-Portals, Multiverse-SignPortals, MyCommand, NametagHide*, NetherWater, NexEngine, PhatLoots, PictureLogin, PlaceholderAPI, Plan, PlayerControl, PlayTime*, ProtocolLib, QuickBar*, RemoteChat*, SeePlayerInventory, ServerRestorer, ShulkerRespawner, SkinsRestorer, SkQuery, Skript, SuperLobby, TAB, Terra, TridentTweaks, VarLight, Vault, ViaBackwards, ViaVersion, VillagerOptimiser, VoidGenerator, WebConsole, WorldBorder, WorldEdit, ZombieApocalypse

And here is console message of villager disappear:
[15:26:42 WARN]: Entity threw exception at skygrid:-165.18265835795947,125.0,70.90465728456638
[15:26:42 WARN]: java.lang.IllegalStateException: No offered ingredients
[15:26:42 WARN]: at com.google.common.base.Preconditions.checkState(Preconditions.java:444)
[15:26:42 WARN]: at org.bukkit.craftbukkit.v1_16_R2.inventory.CraftMerchantRecipe.toMinecraft(CraftMerchantRecipe.java:86)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.EntityVillagerAbstract.a(EntityVillagerAbstract.java:240)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.EntityVillager.eW(EntityVillager.java:827)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.EntityVillagerAbstract.getOffers(EntityVillagerAbstract.java:92)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.EntityVillager.fm(EntityVillager.java:315)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.EntityVillager.fc(EntityVillager.java:353)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.BehaviorWork.a(SourceFile:58)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.BehaviorWork.a(SourceFile:18)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.Behavior.e(SourceFile:49)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.BehaviorGate$Execution$1.lambda$a$1(BehaviorGate.java:85)
[15:26:42 WARN]: at java.util.stream.ReferencePipeline$2$1.accept(Unknown Source)
[15:26:42 WARN]: at java.util.stream.ReferencePipeline$2$1.accept(Unknown Source)
[15:26:42 WARN]: at java.util.stream.ReferencePipeline$3$1.accept(Unknown Source)
[15:26:42 WARN]: at java.util.ArrayList$ArrayListSpliterator.tryAdvance(Unknown Source)
[15:26:42 WARN]: at java.util.stream.ReferencePipeline.forEachWithCancel(Unknown Source)
[15:26:42 WARN]: at java.util.stream.AbstractPipeline.copyIntoWithCancel(Unknown Source)
[15:26:42 WARN]: at java.util.stream.AbstractPipeline.copyInto(Unknown Source)
[15:26:42 WARN]: at java.util.stream.AbstractPipeline.wrapAndCopyInto(Unknown Source)
[15:26:42 WARN]: at java.util.stream.FindOps$FindOp.evaluateSequential(Unknown Source)
[15:26:42 WARN]: at java.util.stream.AbstractPipeline.evaluate(Unknown Source)
[15:26:42 WARN]: at java.util.stream.ReferencePipeline.findFirst(Unknown Source)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.BehaviorGate$Execution$1.a(BehaviorGate.java:86)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.BehaviorGate.a(BehaviorGate.java:44)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.Behavior.e(SourceFile:49)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.BehaviorController.d(SourceFile:506)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.BehaviorController.a(SourceFile:465)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.EntityVillager.mobTick(EntityVillager.java:169)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.EntityVillager.mobTick(EntityVillager.java:166)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.EntityInsentient.doTick(EntityInsentient.java:763)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.EntityLiving.movementTick(EntityLiving.java:2753)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.EntityInsentient.movementTick(EntityInsentient.java:543)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.EntityAgeable.movementTick(EntityAgeable.java:143)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.EntityLiving.tick(EntityLiving.java:2478)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.EntityInsentient.tick(EntityInsentient.java:306)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.EntityVillager.tick(EntityVillager.java:211)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.WorldServer.entityJoinedWorld(WorldServer.java:841)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.World.a(World.java:884)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.WorldServer.doTick(WorldServer.java:526)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.MinecraftServer.b(MinecraftServer.java:1358)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.DedicatedServer.b(DedicatedServer.java:371)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.MinecraftServer.a(MinecraftServer.java:1211)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.MinecraftServer.w(MinecraftServer.java:999)
[15:26:42 WARN]: at net.minecraft.server.v1_16_R2.MinecraftServer.lambda$a$0(MinecraftServer.java:177)
[15:26:42 WARN]: at java.lang.Thread.run(Unknown Source)