I wasn't planning to shoot into the sun
, it just happened that the sun was in a very nice position so I took that shoot without thinking too much about the polarizer. I noticed the above effect at home when playing in Lightroom. It's a Nikon circular polarizer II, I forgot if it's a slim version or not, probably not.
Next time I try something like this and I have the polarizer on I'll try to recall to take it off.