Error when removing aliases with QuickStatements in background mode

[lorenzomarconi]

Steps to replicate the issue: I want to remove a set of aliases from different items in different languages using QuickStatements, so I:

1. go to https://quickstatements.toolforge.org/#/batch
2. insert the following commands:

-Q745	Ahy	"մորի"
-Q17592	Aast	"Avestruz"
-Q7045	Aast	"Samartín"
-Q11575	Azh	"玉米"

3. add a summary
4. click on "Import V1 commands"
5. click on "Run in background"

What happens?: An example batch is here. As you can see, all the commands produce an error.

What should have happened instead?: All the aliases should have been removed.

Other information If I try to click on "Run" instead of ("Run in background"), then everything is fine.

Note that it is not a Unicode-related problem, since it occurs even when only the second row is specified (see e.g. this batch).