Threaded view does not respect date order

I have a problem with the threaded view in Thunderbird. Even though I set the sorting to “by date” with newest messages on top, the conversation view does not follow this order. As you can see in the attached screenshot, the newest message sometimes appears in the middle of the thread, and the order of the replies looks random, as if Thunderbird is “inventing” the sequence instead of respecting the actual message dates. This makes it very confusing to follow conversations, because the chronological flow is broken. Is this a known bug in Thunderbird 140, or is there an additional configuration I need to adjust so that threaded conversations always show the most recent message at the top in correct order? I have 143.0.1 (64-bit) Thank you for your help.