Hmm, my NAS volume mounts very quickly under this method, is you WD NAS attached locally to your Mac? Ooops, I see it is.
See attached, mounts quickly and reliably.
I have the folder mount on boot up and then launch JRiver, I used to have JRiver launch at startup, after the NAS in the boot sequence, but turned that off because I have been tinkering, will turn it on and see if there are any issues in regards to timing.
I have 22,000 music files consuming 1.6 terabytes of disk space, how large is your volume?