Yanay Zimroni

Can confirm for 1.13

[14:36:12] [Client thread/ERROR]: Invalid icon for server localhost (localhost)
 java.lang.IllegalArgumentException: Illegal base64 character a
 at java.util.Base64$Decoder.decode0(Base64.java:714) ~[?:1.8.0_51]
 at java.util.Base64$Decoder.decode(Base64.java:623) ~[?:1.8.0_51]
 at clp.g(SourceFile:212) [1.13.jar:?]
 at clp.a(SourceFile:144) [1.13.jar:?]
 at cgv.a(SourceFile:35) [1.13.jar:?]
 at cha.a(SourceFile:391) [1.13.jar:?]
 at cha.a(SourceFile:194) [1.13.jar:?]
 at clm.a(SourceFile:310) [1.13.jar:?]
 at ctn.a(SourceFile:792) [1.13.jar:?]
 at cfi.c(SourceFile:847) [1.13.jar:?]
 at cfi.a(SourceFile:392) [1.13.jar:?]
 at net.minecraft.client.main.Main.main(SourceFile:144) [1.13.jar:?]

Edit: to clarify, it happens when the game tries to display server icon from an older server (1.12.2 or older)