Fix #17571: Researched rides show up as new vehicles in .park scenarios

distribution/changelog.txt

@@ -24,6 +24,7 @@
 - Fix: [#17541] Station style not correctly saved to TD6.
 - Fix: [#17542] Stalls will autorotate towards paths outside the park.
 - Fix: [#17553] Crash when moving invention list items to empty list.
+- Fix: [#17571] All researched tracked rides show up as new vehicles in .park scenarios.
 - Fix: [#17605] Crash when opening parks which have had objects removed externally.
 - Fix: [#17639] When building upside down, the special elements list contains many items twice (original bug).
 

src/openrct2/management/Research.cpp

@@ -964,6 +964,7 @@ static void research_update_first_of_type(ResearchItem* researchItem)
         return;
     }
 
+    researchItem->flags &= ~RESEARCH_ENTRY_FLAG_FIRST_OF_TYPE;
     const auto& rtd = GetRideTypeDescriptor(rideType);
     if (rtd.HasFlag(RIDE_TYPE_FLAG_LIST_VEHICLES_SEPARATELY))
     {

src/openrct2/park/ParkFile.cpp

@@ -2372,6 +2372,7 @@ public:
     void Import() override
     {
         _parkFile->Import();
+        research_determine_first_of_type();
         game_fix_save_vars();
     }