Why does she curl her feet?

She doesn't do it when walking or running around, however whenever a shoe goes near her she instantly curls her feet.  Which makes it really difficult to get shoes on her, and sometimes it will take a couple of attempts.

I done a bit of research and most of the feedback was because their children didn't like to wear shoes so they would curl their toes, they would scream or try and pull them off, but my little Summer loves wearing her shoes, she tries to put them on herself or she will sit there and try and put my shoes on (she even curls her feet then). She never complains about her shoes, so I really not sure why she curls her feet?

For her it seems to be a natural reflex whenever you try to put shoes on her and I am not sure how to get her out of that habit, I have been hoping for the past couple of months she would grow out of it, but it doesn't look like she will anytime soon!  Over the months I have tried different types of shoes, flat pumps, trainers, boots, slippers, doodles and so on, but for everyone she curls her toes in.

She sometimes makes her foot go into like a little ball, so I have to try and distract her, I also give a gentle tap/massage on the bottom of her foot to relax it, and then quickly put her shoe on, but she then curls in toes in and I have to start again. She doesn't complain either, she just tries to help me put her shoe on. I never had this with any of my three boys, just with her - maybe she is a budding ballerina. :)

Have you ever experienced this before? Maybe you have some hints or tips for me?