We have two setups performing SPI transactions as master.
Operating the IMXRT1060 as master SPI.
One setup has much less noise on its SCK (green line on the attached JPG) and the other has more noise with spikes up to 4V (red line on the attached JPG).
The first one works smoothly communicating with several slave devices @8MHz.
The second one causes the NXP SPI master to endlessly activate its SCK even though we just use single 16 bits transaction.