It seems that I don't get this behavior when Clk_Peri = 24MHz.
May I ask why you need the 19.2MHz for the peripheral clock?
Isn't it possible to use one of the Peripheral clock dividers (8, 16 or 24.5bit)?
Thanks Achim, I'll mess around with those, didn't think of it.
The problem with the circular buffer being reset was that I was debugging, thus getting disconnected, and I reset the buffer on a disconnection. That was a really dumb mistake.
I need 19.2 MHz to speak via UART to another device which runs at 19.2 MHz and I want the baud rate to have minimal error.