php中带有'current'字样的变量名称会添加特殊字符

I am creating a URL to call in PHP.when I use any variable name as 'current_XX' the system truncates my variable and adds special character to my URL.The character '¤' is added.It works fine if I use other variable name, like 'curr_XX'.

code :

$full_url = $url.
'&permanent_address='.$user_area.
'&permanent_city='.$user_city.
'&permanent_state='.$user_state.
'&permanent_pincode='.$user_pincode.
'&current_address='.$user_area.
'&current_city='.$user_city.
'&current_state='.$user_state.
'&current_pincode='.$user_pincode

echo $full_url;

output : permanent_address=Marathalli&permanent_city=Bangalore&permanent_state=&permanent_pincode=¤t_address=Marathalli¤t_city=Bangalore¤t_state=¤t_pincode=