Using casadi+integrator in a different thread

[doppioandante]

Hello, I've developed a DAE system using casadi (only casadi::SX type of terms) and I'm using it for simulation purpose by integrating it using idas (through the casadi interface).
I then wrapped this inside a FMU manually. This is where I found out that the model doesn't give correct results when run in a different thread, which fmpy.gui does and also simulink seems to do. When run through fmpy standard interface, it works correctly.
I would like to give a small reproducer if it's useful, but I wanted to ask beforehand if such a scenario is even supposed to work with casadi? Is the integrator API thread safe?