Refund in treasury bonds

I chose to have part of my tax return to be paid in I series bonds. I recieved a $500 bond check 2 weeks ago but I requested $1500 total. In previous years, I’ve always received the entire portion of the return in bonds together. Separate checks but same day. I figured since they are ordered together they are shipped together? It has been 2 weeks and haven't received the remaining $1000.  Has anyone received their bonds on separate days?