Memory usage graph incorrect

Hi
we are reviewing the memory graph in Libre NMS on a database server and it seems to be incorrect.
If we look at the below graph we can see that the physical memory is showing as 12.21% use and 87.79 free.

When I compare that to the stats on the linux server and I can see the actuals are different. (I know there could be a delay in the LibreNMS update but it seems to be whey out.) Please see the below output from the server

how can this be fixed?

thanks

Gary

Please note that this is an oracle linux server.