BGW320-500 WiFi configuration issues, drops clients and client indicates "bad password"

Only a few months ago I received a BGW320-500 self-install kit to replace our BGW210-700.  (We've had 1G fiber at home for a few years; in suburban Atlanta market.)  During an outage, AT&T CSR *thought* the 210 had failed, I wasn't so sure.  But here we are.

Via the new gateway's web interface and (perhaps a little of the little Smart Home Manager app), I had it up and running quickly.  It appeared to carry over our existing home and guest SSIDs and password settings.

A few times since (yesterday/today as the latest event), I've found that my/my spouse's iPhones randomly disconnect from WiFi, and at times while attempting to reconnect, the iPhone will return an "incorrect password" type of response.

Just now (am away from the house), I looked into the gateway's WiFi settings via the Smart Home Manager app and noticed the app claims embedded space characters are NOT PERMITTED in the passphrase - though the existing passphrases do still have them (always have).  How is this compliant with the IEEE wireless standards?  And, is this just some restriction at the app level, or is this enforced on the gateway? (I haven't yet checked the gateway's web configuration, to see if it restricts there.)

I REALLY don't want to change my passwords for all my WPA devices (there are lots around the house).

Has anyone else had WiFi authentication issues since getting a BGW320?  Any thoughts on what constitutes a "valid" WPA password?

Dave