Fix endless pondering

src/engine/context.rs

@@ -215,6 +215,7 @@ impl Iterator for SearchContext {
                 // If ponder flag is set, the search is completly restarted within the same iteration
                 if self.ponder_flag.load(Ordering::Relaxed) {
                     self.current_depth = 1;
+                    self.forced_depth = 0;
                     self.search_time_start = SystemTime::now();
                     self.stats = SearchStats::default();