What type of suspend is in use? Check with:
cat /sys/power/mem_sleep
Someone else recently started having issues with their device resuming from suspend–maybe a kernel bug, who knows?–and their issue was resolved by switching from suspend-to-disk to suspend-to-RAM.
See the solution here:
Most of the drawbacks of using this method are related to laptop use (suspend-to-RAM continues to draw power while suspended, which can slowly drain a laptop battery). Considering you have a desktop machine, this may be a good solution for you.