ND thick door


The keycam may have failed, example here, the latest design keycam can be easily identified as the colored changed to black. Replace either the keycam or chassis as needed...
 This could also happen if the tailpiece isn't installed in a KIL, FSIC, or SFIC cylinder.  The FSIC driver also could have come loose from the core in the spindle.
Schlage ND-Series tailpieces for extended doors are available by only two means, but are not available to order separately.   If an extended tailpiece is needed, then a complete lock ...
ND locks can be extended up to 6" Extended Outside.  
The dimension between the door and the  Rhodes (RHO) lever return is approximately .3625". This dimension can vary slightly from one lever to another based on finishing processes.