There may very simply not be a "magic wand" to make this go away. This particular bug is old and not a factor of our code for the Weird spell as much as we can determine.
A long while back, I myself spent a lot of time fussing with this spell, trying to make it exactly fit descriptions and work around this particular quirk to no avail. The problem, if memory serves, lies with the nature of Protection vs. Good/Evil in combination with Save vs. Fear. and in how Bioware treats these two in combination which always results in a save failure without an apparent roll. This left us at the time with two options...to change how the spell was defined or write our own Save vs. Fear routine for this one special case. Neither of these were particularly appetizing options, particularly the latter one, as working around Bioware bugs can often be a lost cause and a poor use of limited resources.
DISCLAIMER: This was quite a few years ago, and my memory could be fuzzy. However, I am about 95% certain that the core reason for this lies with a bug in Bioware's handling of Save vs. Fear when Prot. vs. Good/Evil is in effect.
RECOMMENDATION: I'm not a fan of telling people to memorize spawns but be aware of this and either forego Prot. vs. Good/Evil OR be sure True Seeing is in effect any time creatures who might cast out Weird may be encountered.
Regardless of the outcome to this (i.e. orth and/or I having some major epiphany on how to elegantly work around this), thanks for bumping this back into consciousness. There's probably been a lot of communal memory loss over the last 6-7 years.