Hello saurabh,
you information is quite short to get what the exact problem is caused but at first look there are two possiblity you are getting this
- you are passing current record (to timeline item without timeline list)
- max property of your entity set to 1
if this is not, better can you share some oml or POC to help you quickly on this
Thanks and Regards,
Akshay Deshpande