ISR with Node.js works if the ISR memory cache size is set to 0. This setting forces Next.js to load the data from the storage instead of the memory cache. Acquia runs at least 2 node processes on one server. Such processes do not have a shared memory. Therefore, if you set memory cache, there might be different content in memory after revalidation.For more information, see Data Fetching: Incremental Static Regeneration.