Problem/Motivation
I opened #3134245: Run drush imports as user=1 to solve part of the problem. But that solution is very much a sledgehammer solution when perhaps a more valid solution is to just switch the user if entity validation is enabled. This does the latter.
Proposed resolution
Switch to the entity owner if it implements EntityOwnerInterface
Test the latest patch by enabling validation on the destination entity i.e. validate: true.
source:
plugin: d7_node
node_type: page
process:
title: title
type: type
body: body
destination:
plugin: 'entity:node'
validate: true
