diff --git a/suite2p/detection/stats.py b/suite2p/detection/stats.py
index a21b82ae..d67a86d9 100644
--- a/suite2p/detection/stats.py
+++ b/suite2p/detection/stats.py
@@ -56,8 +56,7 @@ class ROI:
     lam: np.ndarray
     med: np.ndarray
     do_crop: bool
-    rsort: np.ndarray = field(default=np.sort(distance_kernel(radius=30).flatten()),
-                              repr=False)
+    rsort: np.ndarray = field(default_factory=lambda: np.sort(distance_kernel(radius=30).flatten()), repr=False)
 
     def __post_init__(self):
         """Validate inputs."""