"Palilalia is often grouped with other complex tic disorders, like echolalia and coprolalia and may sound like stuttering;[3] all can be symptoms of Tourette syndrome,[4] Parkinson's disease,[5] obsessivecompulsive disorder,[6] or autism.[7] Palilalia can also occur in neurological syndromes, such as stroke or epilepsy.[8][9]" - wikipedia
I have OCD, but usually it is not the end of sentences that are repeated in this disorder. Counting out loud, or repeating phrases over and over again(not related to the sentence said before) as fear if they don't say it many times, something bad will happen.( example, I used to say ' just breathe' over and over again for a while...some weird thing where I thought if I didn't say it I would forget to breathe!

Also, sensory issues are not really related to OCD, unless it has to do with washing hands over and over again, having certain order to things, or getting into the car or out of the house in a certain way.
Are you talking about sensory issues like this? Or overload sensory, where your child becomes too sensitized. Or possibly, sensory, where they can't feel hot or cold correctly? Both of the last two definitely mean some other thing is going on.
Could just be a tic, but would follow up with your doctor for further possible evaluation from a neuro.
