Help L2J H5 Multisell Issue

[Wunderkind]

I've linked a GM shop to the community board using multisell lists with null for the L2Npc instance.  I have NO problems getting the multisell lists to load, however I'm finding that at random intervals I cannot make purchases through them.  They all lock up at once, so it doesn't matter which list I try to buy from.  I've tested and found that it has nothing to do with whether I'm in combat, whether I load the list right after I log in or if I move around a bit first, nor does it have anything to do with where I'm located.  However, if I wait a bit and just go about my business for awhile, it will work in a minute or two.  I don't think it has anything to do with my calls to the multisell lists, because they load fine, but perhaps with the L2J code itself.

 

tl;dr Multisell lists are opening, but won't sell at random times.