I think the problem is because the server hangs for a long time while posting and one clicks the send/create button several times. Many websites deal with that with blocking more than one post going through in short time, say 15 seconds. PC may want to fix that annoying problem.
PC needs to fix several things but he doesn't seem to be around anymore......or doesn't care. I think your assessment of the double posts likely is right on target.
i was hoping they were working on it. it worked great for quite awhile. the only thing i can think of is the proliferation of advertising.
I tweeted him earlier in the week when the site was down due to the server. He responded with: Thread submission speed gets fixed in the new software update I'll be installing this week. Also adding Google PageSpeed Service. I think life sometimes gets in the way. I'm certain he cares or the site wouldn't be here.
Please don't get me wrong, I'm not trying to be negative, but providing a constructive criticism. I also frequent dozens of various online forums. I have to say without a hesitation, PC has the absolutely worst forum software. I'm talking slow, freezing, crushes, double posts, and infected with malware. I need to research the underlying engine: Forum software by XenForo™ ©2010-2013 XenForo Ltd. Edit: I guess you get what you pay.
Maybe you should hesitate a little. How do you know that the problem isn't really an overloaded server ?? You don't. I think that this software is loaded with the absolute BEST array of features that I have seen in a long time, maybe ever. The current performance and bugs, however, does suck a big one. P.S. Exactly how many thousands of dollars do you think one should spend on a software license to ensure that there are no bugs ??? (Hint: rhetorical question.)