Index: pymatgen/src/pymatgen/io/lammps/outputs.py
===================================================================
--- pymatgen.orig/src/pymatgen/io/lammps/outputs.py	2025-02-20 11:46:02.871737234 +0100
+++ pymatgen/src/pymatgen/io/lammps/outputs.py	2025-02-20 11:46:02.867737465 +0100
@@ -111,7 +111,7 @@
     """
     files = glob(file_pattern)
     if len(files) > 1:
-        pattern = file_pattern.replace("*", "([0-9]+)").replace("\\", "\\\\")
+        pattern = file_pattern.replace("+",r"\+").replace("*", "([0-9]+)").replace("\\", "\\\\")
         files = sorted(files, key=lambda f: int(re.match(pattern, f)[1]))
 
     for filename in files: