I had this same issue. My girl was like why are you sending gibberish and took a screen shot. I did a search and found the fix (I believe this will fix your issue). Go to Settings -> Send Settings and Turn ON the 'Split large messages' option. Even when mine weren't large or I'd send an emoji or an mms or anything other than a quick reply... it would do it. After applying that, I haven't had an issue since. I love GoSMS esp the new Emoji menu area, my iphone friends are readable now too (after a root/android font install)