hi @AndyG !! Welcome to our community! 
I was not able to reproduce this.
Here are the steps in python I have used:
from weaviate import classes as wvc
collection = client.collections.create(
"Test",
vectorizer_config=wvc.config.Configure.Vectorizer.none(),
multi_tenancy_config=wvc.config.Configure.multi_tenancy(enabled=True),
properties=[
wvc.config.Property(name="text", data_type=wvc.config.DataType.TEXT)
]
)
collection.tenants.create(
["tenant1", "tenant2"]
)
from weaviate import classes as wvc
t1 = collection.with_tenant("tenant1")
t1.data.insert({"text": "a text on tenant 1"})
t2 = collection.with_tenant("tenant2")
t2.data.insert({"text": "a text on tenant 2"})
t1.query.fetch_objects().objects[0].properties
t2.query.fetch_objects().objects[0].properties
# create the backup
client.backup.create(backup_id="first_backup", backend="filesystem")
# delete the collection
client.collections.delete("Test")
# now restore
client.backup.restore(backup_id="first_backup", backend="filesystem")
# this should print
t1 = client.collections.get("Test").with_tenant("tenant1")
print(t1.query.fetch_objects().objects[0].properties)
#>>> {'text': 'a text on tenant 1'}
Also, check your server logs. You should see something like this:
weaviate-1 | {"action":"restapi_request","level":"debug","method":"POST","msg":"received HTTP request","time":"2024-06-11T14:30:20Z","url":{"Scheme":"","Opaque":"","User":null,"Host":"","Path":"/v1/backups/filesystem/first_backup/restore","RawPath":"","OmitHost":false,"ForceQuery":false,"RawQuery":"","Fragment":"","RawFragment":""}}
weaviate-1 | {"action":"try_restore","backend":"filesystem","backup_id":"first_backup","level":"info","msg":"","time":"2024-06-11T14:30:20Z","took":3977084}
weaviate-1 | {"action":"restore","backup_id":"first_backup","class":"Test","level":"info","msg":"successfully restored","time":"2024-06-11T14:30:20Z"}
weaviate-1 | {"action":"restore","backup_id":"first_backup","level":"info","msg":"backup restored successfully","time":"2024-06-11T14:30:20Z"}
Let me know if this helps!
Thanks!