World unload stalls waiting for DLC banner HTTP downloads (1.210.014, no mods)

Observed behavior

After creating/loading a Star System world and choosing Save and Exit to Main Menu, the game remains on the world progress dialog for several minutes. Saving finishes, but returning to the main menu is blocked.

Environment

Space Engineers PC, App Version 01_210_014; Windows 11 x64; .NET Framework 4.8.9363.0. The session log reports "List of used mods (0)" and the saved configuration contains <Mods />. Experimental mode enabled. Installation integrity has not been verified; the log also has missing vanilla music asset warnings.

Timeline (2026-11-07, UTC+8)

13:43:54.938: UnloadAndExitToMenu - Started

13:43:54.990: Session snapshot save - END

Save files were verified on disk with matching timestamps. From 13:43:59 onward, managed threads 9 and 10 continue downloading promo ZIPs from https://crashlogs.keenswh.com/api/banner/ (Prosperity, Economy2, CoreSystems, ApexSurvival, Fieldwork, Contact). The unload was still waiting when live stacks were captured several minutes later.

Main thread stack (abbreviated)

System.Threading.WaitHandle.WaitAll

ParallelTasks.Parallel.WaitForAll

ParallelTasks.PrioritizedScheduler.WaitForTasksToFinish

Sandbox.Game.World.MySession.Unload

Sandbox.Game.World.MySessionLoader.Unload

Sandbox.Game.World.MySessionLoader.UnloadAndExitToMenu

Both managed worker threads 9 and 10 (abbreviated)

System.Threading.WaitHandle.WaitOne

RestSharp.AsyncHelpers.CustomSynchronizationContext.Run

RestSharp.AsyncHelpers.RunSync

VRage.Platform.Windows.Http.MyWindowsHttpClient.DownloadAsync

Sandbox.Game.Screens.MyGuiScreenMainMenuBase.DownloadPromoZip

Sandbox.Game.Screens.Helpers.MyGuiControlDLCBanners.DownloadImages

ParallelTasks.DelegateWork.DoWork

ParallelTasks.WorkItem.DoWork

ParallelTasks.PrioritizedScheduler.Worker.WorkerLoop

Expected behavior

Optional promotional image downloads should not block world unloading. Slow or unavailable downloads should have bounded timeouts and cancellation during session teardown.

Assessment and limits

Stacks strongly indicate that DLC banner network tasks delay session teardown. One observed session; repeatability, exact network failure mode and eventual completion time have not been established. This is a prolonged stall, not a proven permanent deadlock.

Suggested reproduction (not independently validated)

Start with banner downloads slow/unavailable, enter a new unmodded Star System world promptly, then Save and Exit to Main Menu while downloads remain outstanding.

Attached ZIP includes the report, relevant log excerpts and captured worker stacks, with unrelated personal identifiers omitted.