Argument #1 ($value) must be of type Countable|array, null given in hosting_migrate_platform

Problem/Motivation

TypeError: sizeof(): Argument #1 ($value) must be of type Countable|array, null given in hosting_migrate_platform() (line 103 of /var/aegir/hostmaster-7.x-3.x/profiles/hostmaster/modules/aegir/hosting/migrate/hosting_migrate.batch.inc).

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes