The formatting is because you pasted from Discord and this board supports rich formatting, you solve it by pasting first in Word without formatting and then copying it here again, deleting the extra line feed (if you paste in Notepad the app won't be able to read the line feeds properly because they use linux-type line feed without carriage return, so you either need an advanced text editor like JEdit or go with MS Word paste options). Actually scrap all that, the board seems to recognize rich formatting and prompts to paste as plain-text when you put the formatted text in the reply box, works with Discord too.
Regarding the problem, the previous user commented very basic suggestions that I'm sure you have already tested and re-tested by now (knowing your struggle to solve this), but it made me come to mind of an old post on the battlelog forums about relaxing the interval of the Punkbuster client checks in order to have less lag I think it was (improves latency reduction).
In the same battlelog topic, the user ruffler quoted another bit from the fearless-assassins forum boards (incidentally they use Invision software as well), specifically mentioning the command number 4. Keep in mind this is a 2009 post so the dual core stuff at the bottom is a bit old, but it actually still applies; also the post was written for the game "ET" and not "BF2" but still, the mechanism should be the same. Commands can be issued in console but I don't know if the others can be written permanently in the pbcl.cfg file(s):