[BirdOPrey5]

I never did figure it out really... instead of doing the replacements on bbcode_parse_start and bbcode_parse_complete_precache I instead did them on postbit_display_complete, newpost_preview, and newreply_form_reviewbit and I didn't run into the cache issues with these hooks.

The down side is that I needed 3 plugins instead of 2 and it won't work if I ever needed to use the bb code outside a post (say in a social group or signature) but I won't so it's not a big deal- otherwise I'd need even more plugins for those locations.