Hi,
CLK low pulse is caused by using first workaround for ERR050456, that is resetting LPSPI module.
If you select 2 workaround, a low pulse would not appear. From RTD300 2nd workaround is properly implemented.
To enable the 2nd workaround, you need to define a macro ERR_IPV_LPSPIV2_0001 and ERR_IPV_LPSPIV2_0001_2ND_SOLUTION
RTD_SPI_UM.pdf:
Anyway, if connected device is enabled by the CS, this SCK extra pulse brings no issue.
BR, Petr