Just chiming in here.
I've had this issue on AC20 for a while now. I don't think it's a ram issue, I've got plenty and it happened one day out of the blue, then started a few month later on my laptop.
I've been getting around it by hitting render (getting failed render) then as quickly as possible re-rendering. It seems cinerender takes too long to start but once it's running you can jump on the back of that last startup.
Personally I think due to a win 10 update, hence the delay of the issue between devices. Re-install of software should fix the issue, but this workaround works for me at the moment.
Versions 10 to 27
Metabox Prime-X P775DM2-G (Clevo),
GTX 1060 6GB GDDR5 VRAM - G-Sync,
i7-6700K (8M Cache up to 4.2 GHz),
32GB DDR4 2133MHZ,
512GB SATA 3 M.2 SSD,
Win 11 64