Unable to Enable/Disable Polling/Alerting in Device Port Menue

It's possible to enable/disable polling/altering of ports in the device menue. BUT on switches with lots of ports i have a problem to change this for ports with higher ID's.

Example: Cisco Catalst 6500, 245 Ports.

Ports 1 - 130 are changeable
Ports > 130 the switcher goes to enable/disable but after saving the front end says: "Device record unchanged. No update necessary"

The count after ports aren't able to change is not an accurate count, it differs between 120-150. Sadly, have no time to figure out under which conditions the number varies.

Changes directly to the mysl ports table are recognized and correctly shown in the frontend.