Module settings not saving

We have had this issue on a few sites that we are using the module, but haven't seen any others mention it

Steps to reproduce the behavior:
1. Go to Event Module Settings
2. On 2 different sites, we have under the General Tab, "Filter Events by Category", I would select one of the categories, click save, and none of the changes take affect. Have experienced the same issue under the Display tab, "Events List Settings", "Select Events by Number" changed from 2 to 5 for example, and click save, and no changes take affect.