You didn't provide much info (especially, you did not bother to say what interface was there in the first place), but given your routing mark names, I assume that all these rules are related to a dynamic VPN interfaces, most likely you are running server and clients are connecting and everytime client connects, it creates an interface. That would explain everything:
Dynamic interfaces (notice the "D" letter on beginning row) are dynamic. If the tunnel/vpn is down (or router is rebooted), interface is removed. Next time it is created, it is actually different interface. This is expected behavior.
You have following choices:
1) Create a "server binding" interface (interfaces->add -> select corresponding type based on your VPN type) for each username. Then, this interface will not disappear once user disconnects, instead, it will just turn off "running" state.
2) create an "interface list" (interfaces-> lists -> add) and then, in your PPP profile, select this list. Once dynamic interfaces are created, they will be instantly assigned to selected list. In your firewall/routes, use this interface list instead of specifying particular interface.
The first option will give you more flexibility, but you have to create the interface for every single user and you can't have multiple interfaces for one user.
The second option means less flexibility and maybe not suitable for you at all because all interfaces within the list will have same route or firewall rule applied, but it is easier to set up because all you need is a single list.