Large number of interfaces (MX960) makes it impossible to deselect interfaces

I added a Juniper MX960 with many interfaces (few hundred interfaces including subinterfaces, etc.) to Observium. I then tried to deactivate all interfaces in the port configuration for the device but that was impossible. The first interfaces worked fine but after that Observium would not save the interface poller/alarm changes. When I manually deactivated an interface down at the bottom of the list Observium would just tell me "No changes to device configuration" instead of deactivating the interface.

I couldn't find a pattern on which interface(s) this occurs but it occurs all the time.