Well, I'm running mostly stock FS2 tables (only additions are Hamano's Boreas, Orion Phase 2, and Herc 3), and just playing with the beams on primary hardpoints, I came across this.
The beams aren't staying 'on' like a beam should. They flicker, the rate being the refire delay specified in the weapons.tbl, apparently. Unless something's changed in the specifications for a fighter beam that I didn't catch, something's broken that particular block of code. They're drawing as a proper beam, though, and all the proper fire points project them.
I'm not submitting to Mantis until I've gotten confirmation that something's actually wrong.