• 1. Perform this command (in a command block):

     /setblock ~ ~ ~ standing_sign 0 replace {Text1:"1.",Text2:"{\"text\":\"POWER REDSTONE LAMP\",color:dark_red,bold:true}"}
     

The sign will only say:
1.
POWER

But when you perform this command (in a command block):

/blockdata ~ ~-1 ~ {}

You will get this as last output (or at least something similar):

[12:29:15] The data tag did not change: {id:"Sign",Text1:"\"1.\"",Text2:"{\"bold\":true,\"color\":\"dark_red\",\"text\":\" 
POWER REDSTONE LAMP
\"}",Text3:"null",Text4:"null",z:619,y:56,x:1243,}

Which poofs that the sign cuts off the text (without the spaces between the words it wont)

It seems like the game is calculating for every character 2 spaces when bold selected, because when you set bold to false, it works