It is well known that quantum theory is ridden with foundational problems such as the measurement problem, nonlocality, wavefunction collapse, etc. Moreover, it seems that all those problems continue to persist even in relativistic quantum field theory. However, does string theory help resolve or understand those foundational problems in any manner?
String Theory builds on the same foundation laid by QFT, which builds on the same foundation laid in QM. Generally the laws that yield probabilities - which lead to scattering cross sections - are the same in these theories. They share the same general framework, and the notion of "measurement" is not any more well-defined in any of them.