What were you doing when the issue happened?

After leaving a server and rejoining it, it says "incomplete set of tags received from server". Without Bluepower everything works fine.

Java Debugger output

Render thread[1] # catch all java.lang.IllegalStateException
Render thread[1] # now continue until the right exception is hit
Exception occurred: java.lang.IllegalStateException (to be caught at: mezz.jei.load.PluginCaller.callOnPlugins(), line=28 bci=91)"thread=Render thread", net.minecraft.tags.TagRegistry$NamedTag.func_232944_c_(), line=131 bci=41
Render thread[1] dump this
this = {
defaults: null
defaulted: false
net.minecraft.tags.TagRegistry$NamedTag.field_232942_b_: null
net.minecraft.tags.TagRegistry$NamedTag.field_232941_a_: instance of net.minecraft.util.ResourceLocation(id=62444)
}
Render thread[1] dump this.field_232941_a_
this.field_232941_a_ = {
field_240908_a_: instance of com.mojang.serialization.Codec$1(id=62445)
field_200118_c: instance of com.mojang.brigadier.exceptions.SimpleCommandExceptionType(id=62446)
field_110626_a: "bluepower"
field_110625_b: "saw"
}

Forge and Minecraft version

1.16.4 - 35.1.37

Bluepower version and build number

1.16.4-0.5.223-alpha

Your using a very old version here but I've been unable to replicate this issue, please provide the full log file?

Downloaded your Modpack and was able to replicate the issue, updating bluepower and the other mods fixed the issue, I wasn't able to narrow it down to a specific mod but potentially JEI.