Jsprit can't find optimal solution for TSP instances

Is it normal if Jsprit returns non-optimal solution for low dimension TSP_lib instances?
For example, if I try to solve bays29.TSP using regret insertion, it never returns the optimal solution, until I use Best insertion heuristic.
For the rest of TSP_lib instances, it is impossible to get an optimal known solution. Until now I can solve most of CVRP, VRPTW … without any problem.
Can someone, please, tell me what I did wrong? , I use Jsprit to solve TSP the same way I use it for VRP. To read the problem, I use TSPlib reader given with Jsprit.
Thank you for your help.

It is because RegretInsertion is not suitable for TSP at all. Just look at the nature of RegretInsertion … you can only reasonably apply it when dealing with VRP.

Thank you @stefan for your reply. I didn’t know that. I’ll work more on regret insertion to understand it.