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What's your Arduino IDE version?
Arduino pin 52 is the one SS pin that's a B peripheral (PB21) rather than an A peripheral,
perhaps the PIO needs configuring to use B peripheral on that pin?
@blueminerals, why'd you remove your question?
Actually I think its worst than that, pin 52 cannot work as SPI since the relevant
PIO pin (PA30) is not brought out on the package at all (except for the 217 pin
version only available on an evaluation board). Arduino pins 4 and 10 both
connect to two pins each on the package to get SPI functionality, as far as I can tell,
presumably the same was intended for 52 except that PA30 isn't pinned out!