CCR1016 ROS 7.15.3(ROS 7.13 no changes)
- ROS ingores AS path and choose 2 routes.
- It looks like BGP ECMP, but status of BGP multipath feature is N/A.
There is no issue on CCR1036 with same configuration and same version.

CCR1016 ROS 7.15.3(ROS 7.13 no changes)

Set BGP properly so that all sessions run on the same BGP instance.
It is.

It is.

A remote address and/or common template does not mean that the session runs on the same instance. See documentation for more info:
https://help.mikrotik.com/docs/display/ROS/BGP#BGP-RunningMorethanOneInstance
It helps. Thank you!