OMG!! YES!!! we called them " sh** storms".. Despite being potty trained to pee on the musical potty since 12 months, she would not go poop in the pot until 31/2 -4 yrs old and then ONLY in the potty at home...
Aside from just being on top of her during nap/bed time, there was no stopping her... it was a phase and it simply played itself out..
however, the poop smearing and reluctance to pooop in the potty is not uncommmon with kids with sensory issues.. my daughter is 10 now and DX'd as aspergers w adhd and sensory integration disorder.. of course we didnt know it back then, but as i got to speak to other parents with kids with sensory issues i found I was NOT ALONE!! lol
try getting her to sit backwards or forwards on the toilet with her feet up so she can see her body in action ... it was like watching labor... "here it comes!! PUUUSSSHHHHH!!!" until she finally delivered a healthy bm!!
Then of course, reward her handsomely immediatly and each time you can get her to do it... my kid got ice cream every day for 2weeks because i was so grateful that the sh** storms were over!!
I also recently found this online for a friend having similiar problems...seemed interesting & worth a try
In my classroom right know I am working on three six years being potty trianed. We made a box and divided it half, with a icon of pee (yellow side) and poop (brown side). EVERYTIME they go pee the get a small tressure, and larger items are saved until they go poop. When they go poop in the toilet they get the bigger tressure.But we try to make it fun and when they have acciedents we remind "It okay, but next time in the toilet and you can have your tressure." The items will deffer depending on the child. The school can carry this over to. It helps if everyone is on board
HANG IN THERE!!! GOOD LUCK!!