I had several issues with LCIRs and zn510s. Most problems involved all or some values not showing up. In each case the problem was resolved by deleting the device in 'device manager' and rediscovering and adding again. Occassionally this took more than one attempt to come out right but now everything is working ok.
ive seen it with LCIRs before, like you said, delete and rediscover always resolves that. Not sure what the deal is, however i have seen tridium panels installed with a termination module on the link, inplace of EOL resistors. I know lon says use resistors but the site i frequent the most has the termination module and if i have to re-commission a LCIr it usually takes a couple of tries. It could be the comm link causing the problem due to the lack of EOL resistors.