Commandblock with a long "execute if score" command kicks the player

I try to enter a command in an commandblock and get kicked with the following message: "Internal Exception: io.netty.handler.codec.DecoderException: The received string length is longer than maximum allowed (294 > 256)". After that I can join like nothing has ever happend.

Works fine in Singleplayer. If I write a command with notepad an paste it in everything works also.

The Server console displays the same message:

[20:35:05 INFO]: YouCreeperLP lost connection: Internal Exception: io.netty.handler.codec.DecoderException: The received string length is longer than maximum allowed (294 > 256)
[20:35:05 INFO]: YouCreeperLP left the game

How to reproduce:
Step 1. Start a 1.13 Server
Step 2. Place a commandblock
Step 3. Enter the following command(Just a long execute command with an "if score" at the end)
Step 4. Press "space"

Command:

execute if entity @a[nbt={SelectedItem:{id:"minecraft:iron_shovel",tag:{Unbreakable:1b,display:{Lore:["415489674896541865418657441564198654986547168523410865327419865327489653748965748657418965418965418654186541685341685234186541685416574416524165234165234168523416523416532156"]}}}}] if score

Also happens with "store result score" at the end. So I suppose it has something to do with scoreboard. It dosn't matter if any scoreboard objectives exist or not.

I searched and found similar Bug reports but they were fixed.