Thanks for the query.
Rarely there is possibility of some damage to cervical tissue while applying cervical stitch to incompetent cervix
Usually that will heal up after few weeks of delivery.
Rarely some tissue may remain hanging down.
One more possibility is presence of cervical erosion, that can present with spotting.
As you had normal delivery there is less possibility for other causes like presence of vaginal septum etc.
So you once consult gynecologist and get examined to find out the exact cause.
Then depending on the cause treatment can be taken.