You could try to use wireshark/tcpdump to see how SNMP requests and replies travel between your NNMi station and devices in question, possibly the reply comes too late, and increasing number of retries or timeout length will help here. Just keep in mind that each retry increases timeout in 2. Currently you have 0.8 timeout and 2 retries, it means that if device is not responding, first timeout will be 0.8 seconds, then 1.6 seconds, then 3.2 seconds, making it 5.6 seconds in total before NNM stops waiting for reply.
I set timeout to 2 sek and set 3 retries but I still have a problem. Yesterday I recived info like in attachment: i can read that my polling interval is 10 sek, but in data coll... i set 1 minute. Why in message is 10 sek?