chore: changelog, add note to fixed code

Author: gardenerik

CHANGELOG.md

@@ -3,6 +3,12 @@
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project uses the `YYYY.N` version format.
 
+## 2025.16 - 2025-11-21
+
+### Fixed
+
+- Problem scanning would sometimes cause deadlock of the database.
+
 ## 2025.25 - 2025-11-19
 
 ### Added

bullet/problems/logic/results.py

@@ -107,6 +107,8 @@ def _set_solved_problems(rr: ResultRow):
         .values_list("id", flat=True)
     )
 
+    # These two queries are separated in order to prevent
+    # locking the Problem table.
     problems = SolvedProblem.objects.filter(id__in=problems).values_list(
         "problem__number", flat=True
     )