Hello,
I’m currently looking through changes to the relevant code that happened between 4.25 and 4.26.1 to see if I can find any likely culprits for this altered behavior. I am noticing that there are a few recent CLs in GitHub that looked like they were created to solve similar issues to this: can you let me know if syncing to the changes on these two CLs fixes the problem?
Otherwise, can you try entering the following commands into the console, and letting me know what happens?
au.streamcache.BlockOnChunkLoadCompletion 1
au.streamcache.DispatchToGameThreadOnChunkRequest 0
This should disable the only major code changes to the relevant functionality that I’ve seen introduced in 4.26, so knowing if this is the source of the problem significantly narrows down where to investigate.
Otherwise, the next thing to look at would be the stream caching settings.