Different monitoring tools present the concept of "free" vs "available" memory differently, which can be highly misleading. The only one I pay any attention to anymore is free -m, please see my CPX 2024 slide deck for how to properly interpret the output of this command:
Be Your Own TAC: Advanced Gateway Troubleshooting Commands
Bottom line is ignore the "free" value and focus on the "available" value, hopefully there are separate OIDs for each of these.
Attend my 60-minute "Be your Own TAC: Part Deux" Presentation
Exclusively at CPX 2025 Las Vegas Tuesday Feb 25th @ 1:00pm