I think this is a change in policy from a year or two ago. If it says 4/20 - well, that's how long they're going to hold them. I'm not 100% sure about that.
You can send them an email asking them if it is an error - it just may be. I requested Hyatt checks and they were out of stock, so the pending date reflected the date they expected to get them. I received them early.
I still use them to get Hyatt checks, which I find to be a pretty good value. I guess I should start doing my homework to see if I can do better using a different shopping portal.