[1.12.2] Literal % coloured with TextComponentTranslation

I have some coloured text in my "en_us.lang" file, like:

testkey=§9Blue %% Blue

I want to use it in a TextComponentTranslation, but it places §r around the % for some reason, so the second Blue isn't blue

TextComponentTranslation c = new TextComponentTranslation("testkey");
System.out.printf("I18n.format: %s\n", I18n.format("testkey"));
System.out.printf("TextComponentTranslation: %s\nUnformatted: %s\nFormatted: %s\n", c, c.getUnformattedText(), c.getFormattedText(), c);

I18n.format: §9Blue % Blue
TextComponentTranslation: TranslatableComponent{key='testkey', args=[], siblings=[], style=Style{hasParent=false, color=null, bold=null, italic=null, underlined=null, obfuscated=null, clickEvent=null, hoverEvent=null, insertion=null}}
Unformatted: §9Blue % Blue
Formatted: §9Blue §r%§r Blue§r

What's a workaround? Or am I supposed to use the unformatted text?