running the /fb addbackpack command twice in a row creates lots of errors

[456dev]

you can see that the first command doesent fully finish (no backpack added successfully message)
then, on the new command, id doesnt let an id be entered, there are errors in the server console

https://cdn.discordapp.com/attachments/400373256269594627/745600634727825408/unknown.png

[Server thread/INFO]: the456gamer issued server command: /fb addbackpack
[Server thread/INFO]: the456gamer issued server command: /fb addbackpack
[Server thread/WARN]: [FancyBags] Plugin FancyBags v1.6.5 generated an exception whilst handling conversation input
java.lang.NullPointerException: null
	at me.chickenstyle.backpack.prompts.IdPrompt.acceptValidatedInput(IdPrompt.java:26) ~[?:?]
	at org.bukkit.conversations.NumericPrompt.acceptValidatedInput(NumericPrompt.java:37) ~[Server_spigot-1.16.2.jar:git-Spigot-379750e-9a9c223]
	at org.bukkit.conversations.ValidatingPrompt.acceptInput(ValidatingPrompt.java:30) ~[Server_spigot-1.16.2.jar:git-Spigot-379750e-9a9c223]
	at org.bukkit.conversations.Conversation.acceptInput(Conversation.java:234) ~[Server_spigot-1.16.2.jar:git-Spigot-379750e-9a9c223]
	at org.bukkit.craftbukkit.v1_16_R2.conversations.ConversationTracker.acceptConversationInput(ConversationTracker.java:59) ~[Server_spigot-1.16.2.jar:git-Spigot-379750e-9a9c223]
	at org.bukkit.craftbukkit.v1_16_R2.entity.CraftPlayer.acceptConversationInput(CraftPlayer.java:1241) ~[Server_spigot-1.16.2.jar:git-Spigot-379750e-9a9c223]
	at net.minecraft.server.v1_16_R2.PlayerConnection$2.run(PlayerConnection.java:1551) ~[Server_spigot-1.16.2.jar:git-Spigot-379750e-9a9c223]
	at net.minecraft.server.v1_16_R2.MinecraftServer.b(MinecraftServer.java:1072) ~[Server_spigot-1.16.2.jar:git-Spigot-379750e-9a9c223]
	at net.minecraft.server.v1_16_R2.DedicatedServer.b(DedicatedServer.java:352) ~[Server_spigot-1.16.2.jar:git-Spigot-379750e-9a9c223]
	at net.minecraft.server.v1_16_R2.MinecraftServer.a(MinecraftServer.java:1007) ~[Server_spigot-1.16.2.jar:git-Spigot-379750e-9a9c223]
	at net.minecraft.server.v1_16_R2.MinecraftServer.w(MinecraftServer.java:846) ~[Server_spigot-1.16.2.jar:git-Spigot-379750e-9a9c223]
	at net.minecraft.server.v1_16_R2.MinecraftServer.lambda$0(MinecraftServer.java:164) ~[Server_spigot-1.16.2.jar:git-Spigot-379750e-9a9c223]
	at java.lang.Thread.run(Thread.java:834) [?:?]