Improve reason str fmt, add further check for missing potcar spec

Author: esoteric-ephemera

pymatgen/io/validation/check_incar.py

@@ -872,7 +872,8 @@ def _check_parameter(
         if not valid_value:
             error_list.append(
                 f"INPUT SETTINGS --> {input_tag}: is {current_value}, but should be "
-                f"{operation} {reference_value}. {append_comments}"
+                f"{'' if operation == 'auto fail' else operation + ' '}{reference_value}."
+                f"{' ' if len(append_comments) > 0 else ''}{append_comments}"
             )
 
     def check_parameter(

pymatgen/io/validation/check_potcar.py

@@ -50,7 +50,7 @@ def check(self, reasons: list[str], valid_input_set: VaspInputSet, structure: St
         if not self.potcar_summary_stats:
             return
 
-        if potcars is None:
+        if potcars is None or any(potcar.get("summary_stats") is None for potcar in potcars):
             reasons.append(
                 "PSEUDOPOTENTIALS --> Missing POTCAR files. "
                 "Alternatively, our potcar checker may have an issue--please create a GitHub issue if you "