CustomStringBlockFormatter delimiters configuration is not sent correctly to the extension

[johanneshayry]

new CustomStringBlockFormatter.Builder()
	.blocks( 0, 3, 3, 4 )
	.delimiters( "(", ") ", "-" )
	.numeric()
	.build()
	.extend( this )
	;

and when we enter a value in the field, we get this:

(360) 555) 1212

after the 2nd set of numbers, the string ") " is presented instead of "-". We cannot figure out what we are doing wrong. Any ideas?