Thanks for your replay! - The code can be executed without error. If you comment-in line l103:
prob = Optimization.OptimizationProblem(objective, initial_parameters, SciMLBase.NullParameters(),; lb = lower, ub = upper)
The message starts with:
ERROR: All methods for the model function `f` had too few arguments. [...]
The object function objective that causes the issue is compatible to Optim.optimize(),
but not to Optimization.OptimizationProblem().