Return of the two-tone clematis

I wrote, briefly, about it last year, how the clematis outside of my home office window appeared to have two different colours of flowers.

This year, after a really late start, the two different colours are WAY more obvious. Is this a fluke? Is there actually 2 different plants growing here?

edited to add: my mom (who knows everything botanical) says these aren't clematis but are instead morning glory and two colours isn't unusual. Wish she'd move closer and help me figure out what is what in my garden... and maybe weed it for me too :)