Both the reference manual and the data sheet for the MK22DX256VLF5 list pin 33 as I2S0_TXD1 (for MUX alt 6), but every other source indicates that the part has only one I2S transmit line. Here's the page in the reference manual.
This nearly bit me - I was porting a project from another K22 part with two I2S transmitters and used that table to verify that it did have a second TXD, because it was the quickest place to find the information. Thankfully that second TXD didn't turn out to be needed on this board.
I've gotten so frustrated with the documentation that I've started compiling my own quick reference for each part I use. Rather than flipping through three sections of the manual every time I need to figure out what the clock sources for a particular module are, for example, I'm taking a little longer to write it up in the most concise format I can.
If someone else has already started a project like this, I'd love to see it. If I get one part's quick reference completed, I'll share it in case anyone else finds it useful, and to use as a template for other parts.