Text message is being divided into two messages
A single SMS can hold up to 160 characters. But that's only for text. 
Since smartphones make a lot of use of emojis, the SMS cannot hold 160 characters anymore if you include an emoji. AFAIK, the default emoji (smiley) will take 2 characters, but the one with a custom skin tone can take 4 characters. Similarly, it varies from device to device and what kind of emoji it supports.