So the server had plenty of free RAM. But NUMA node 1 was in a pinch. And SSIS spooled its buffers to disk. Doggone it.
I guess I’d figured that notifications were sent based on server-wide memory state. But I guess maybe memory state on each NUMA node can lead to a memory notification?
The target SQL Server instance, a beefy one, was also on this physical server. There’s 1.5 TB of RAM on the server. 🙂
It also looks like the easiest fix is something which was deprecated in Windows Server 2012 R2.