Hi @ferdinand, Thank you for moving this topic to its correct category. Although I believe we agree on the C++ meaning of static members I really wasn't aware that the use of static plugin parameters and static plugin state could in practice be as problematic as you describe and will certainly heed your advice to no longer use static plugin state. Also, your point on field members and parallel execution of member functions is well taken. Thanks again!

@ferdinand Thank you very much for your elaborate answer! Explaining the difference between the interface layer and the plugin layer was very enlightening. I now understand that calling functions more than once is all part of the package and that this does not refer to the actual plugin instance. Thank you again.