diff --git a/test_runner/fixtures/pageserver/utils.py b/test_runner/fixtures/pageserver/utils.py
index b75a480a63..a74fef6a60 100644
--- a/test_runner/fixtures/pageserver/utils.py
+++ b/test_runner/fixtures/pageserver/utils.py
@@ -430,12 +430,17 @@ def enable_remote_storage_versioning(
     return response
 
 
-MANY_SMALL_LAYERS_TENANT_CONFIG = {
-    "gc_period": "0s",
-    "compaction_period": "0s",
-    "checkpoint_distance": 1024**2,
-    "image_creation_threshold": 100,
-}
+def many_small_layers_tenant_config() -> Dict[str, Any]:
+    """
+    Create a new dict to avoid issues with deleting from the global value.
+    In python, the global is mutable.
+    """
+    return {
+        "gc_period": "0s",
+        "compaction_period": "0s",
+        "checkpoint_distance": 1024**2,
+        "image_creation_threshold": 100,
+    }
 
 
 def poll_for_remote_storage_iterations(remote_storage_kind: RemoteStorageKind) -> int:
diff --git a/test_runner/regress/test_s3_restore.py b/test_runner/regress/test_s3_restore.py
index 9992647e56..c1a80a54bc 100644
--- a/test_runner/regress/test_s3_restore.py
+++ b/test_runner/regress/test_s3_restore.py
@@ -8,9 +8,9 @@ from fixtures.neon_fixtures import (
     PgBin,
 )
 from fixtures.pageserver.utils import (
-    MANY_SMALL_LAYERS_TENANT_CONFIG,
     assert_prefix_empty,
     enable_remote_storage_versioning,
+    many_small_layers_tenant_config,
     wait_for_upload,
 )
 from fixtures.remote_storage import RemoteStorageKind, s3_storage
@@ -33,7 +33,7 @@ def test_tenant_s3_restore(
 
     # change it back after initdb, recovery doesn't work if the two
     # index_part.json uploads happen at same second or too close to each other.
-    initial_tenant_conf = MANY_SMALL_LAYERS_TENANT_CONFIG
+    initial_tenant_conf = many_small_layers_tenant_config()
     del initial_tenant_conf["checkpoint_distance"]
 
     env = neon_env_builder.init_start(initial_tenant_conf)
@@ -50,7 +50,7 @@ def test_tenant_s3_restore(
     tenant_id = env.initial_tenant
 
     # now lets create the small layers
-    ps_http.set_tenant_config(tenant_id, MANY_SMALL_LAYERS_TENANT_CONFIG)
+    ps_http.set_tenant_config(tenant_id, many_small_layers_tenant_config())
 
     # Default tenant and the one we created
     assert ps_http.get_metric_value("pageserver_tenant_manager_slots", {"mode": "attached"}) == 1
diff --git a/test_runner/regress/test_storage_controller.py b/test_runner/regress/test_storage_controller.py
index 94d71a7677..b3464b0c91 100644
--- a/test_runner/regress/test_storage_controller.py
+++ b/test_runner/regress/test_storage_controller.py
@@ -23,11 +23,11 @@ from fixtures.neon_fixtures import (
 )
 from fixtures.pageserver.http import PageserverHttpClient
 from fixtures.pageserver.utils import (
-    MANY_SMALL_LAYERS_TENANT_CONFIG,
     assert_prefix_empty,
     assert_prefix_not_empty,
     enable_remote_storage_versioning,
     list_prefix,
+    many_small_layers_tenant_config,
     remote_storage_delete_key,
     timeline_delete_wait_completed,
 )
@@ -654,7 +654,7 @@ def test_storage_controller_s3_time_travel_recovery(
         tenant_id,
         shard_count=2,
         shard_stripe_size=8192,
-        tenant_config=MANY_SMALL_LAYERS_TENANT_CONFIG,
+        tenant_config=many_small_layers_tenant_config(),
     )
 
     # Check that the consistency check passes
diff --git a/test_runner/regress/test_tenant_delete.py b/test_runner/regress/test_tenant_delete.py
index dadf5ca672..448a28dc31 100644
--- a/test_runner/regress/test_tenant_delete.py
+++ b/test_runner/regress/test_tenant_delete.py
@@ -9,9 +9,9 @@ from fixtures.neon_fixtures import (
 )
 from fixtures.pageserver.http import PageserverApiException
 from fixtures.pageserver.utils import (
-    MANY_SMALL_LAYERS_TENANT_CONFIG,
     assert_prefix_empty,
     assert_prefix_not_empty,
+    many_small_layers_tenant_config,
     wait_for_upload,
 )
 from fixtures.remote_storage import RemoteStorageKind, s3_storage
@@ -76,7 +76,7 @@ def test_tenant_delete_smoke(
 
     env.neon_cli.create_tenant(
         tenant_id=tenant_id,
-        conf=MANY_SMALL_LAYERS_TENANT_CONFIG,
+        conf=many_small_layers_tenant_config(),
     )
 
     # Default tenant and the one we created
@@ -215,7 +215,7 @@ def test_tenant_delete_races_timeline_creation(neon_env_builder: NeonEnvBuilder)
     # (and there is no way to reconstruct the used remote storage kind)
     remote_storage_kind = RemoteStorageKind.MOCK_S3
     neon_env_builder.enable_pageserver_remote_storage(remote_storage_kind)
-    env = neon_env_builder.init_start(initial_tenant_conf=MANY_SMALL_LAYERS_TENANT_CONFIG)
+    env = neon_env_builder.init_start(initial_tenant_conf=many_small_layers_tenant_config())
     ps_http = env.pageserver.http_client()
     tenant_id = env.initial_tenant
 
@@ -330,7 +330,7 @@ def test_tenant_delete_scrubber(pg_bin: PgBin, neon_env_builder: NeonEnvBuilder)
 
     remote_storage_kind = RemoteStorageKind.MOCK_S3
     neon_env_builder.enable_pageserver_remote_storage(remote_storage_kind)
-    env = neon_env_builder.init_start(initial_tenant_conf=MANY_SMALL_LAYERS_TENANT_CONFIG)
+    env = neon_env_builder.init_start(initial_tenant_conf=many_small_layers_tenant_config())
 
     ps_http = env.pageserver.http_client()
     # create a tenant separate from the main tenant so that we have one remaining
diff --git a/test_runner/regress/test_timeline_delete.py b/test_runner/regress/test_timeline_delete.py
index 6d96dda391..328131cd08 100644
--- a/test_runner/regress/test_timeline_delete.py
+++ b/test_runner/regress/test_timeline_delete.py
@@ -16,9 +16,9 @@ from fixtures.neon_fixtures import (
 )
 from fixtures.pageserver.http import PageserverApiException
 from fixtures.pageserver.utils import (
-    MANY_SMALL_LAYERS_TENANT_CONFIG,
     assert_prefix_empty,
     assert_prefix_not_empty,
+    many_small_layers_tenant_config,
     poll_for_remote_storage_iterations,
     timeline_delete_wait_completed,
     wait_for_last_record_lsn,
@@ -782,7 +782,7 @@ def test_timeline_delete_resumed_on_attach(
     remote_storage_kind = s3_storage()
     neon_env_builder.enable_pageserver_remote_storage(remote_storage_kind)
 
-    env = neon_env_builder.init_start(initial_tenant_conf=MANY_SMALL_LAYERS_TENANT_CONFIG)
+    env = neon_env_builder.init_start(initial_tenant_conf=many_small_layers_tenant_config())
 
     tenant_id = env.initial_tenant