If I update the FSRS parameters (by optimization or manually) and then use the FSRS simulator before saving the preset options, the simulator uses the memory states saved in the cards (i.e., the states generated from the previous parameters).

Possible solutions:

• If the parameters have been updated, ask the user to save the preset options when they try to use the simulator.
• If the parameters are not the same as the saved parameters, don't use the memory states stored in the cards. Rather, calculate the memory states on the fly (but don't save them to the card).