I've had this issue as well, and is been persistent across several ROMs, all that had been done with a clean install. Slimkat, the unfortunately defunct Nameless, Omni, and Carbon. I don't think it's a specific ROM issue. I would like to know more as well and get a dev's opinion. Oddly, the newest Slimkat has an option in message settings to split sms, but after 160 characters it just stops typing
LG G2 (LS970)
Horsepower is how fast you can hit a guardrail. Torque is how far you drag it.