The only major difference between Lightsail vs a local server would be the amount of CPU available, which lead to difference in performance during garbage collection.
Considering the size of the JSON file being downloaded in the HTTP Request node, and that the Lightsail server has likely only one core available, I have a strong suspicion that garbage collection has something to do with this issue.
The reason I asked for testing other versions was because somehow I got the impressions that things were better before 216.2. But now that I read the thread again, I’m not sure what made me come to that conclusion. Sorry about that.
That said, I’m still not sure why queue mode would take more memory than main mode in this case 