1. View https://www.mediawiki.org/wiki/Talk:Compatibility
2. Click "Browse topics" and scroll down in the list of topics to the 15th topic or lower in the list (basically any topic that hasn't already been preloaded on the page and needs to be lazy-loaded).
3. Once the interface is done taking you down to section 15 and it loaded it, now slowly scroll back up, which should lazy-load topic 14, 13, 12 etc.

Instead:

Network debug
The following request is made repeatedly whenever I touch the trackpad to scroll up another pixel. Which means it keeps retrying. This is confirmed by the red error being replaced by a gear-spinner animation, and then back to another red error, and this repeats itself after every scroll event.

• https://www.mediawiki.org/w/api.php?action=flow&format=json&page=Talk%3ACompatibility&submodule=view-topiclist&vtloffset-dir=rev&vtllimit=10&vtloffset=20140808101405&vtlsortby=updated
• {"servedby":"mw1227","error":{"code":"internal_api_error_DBQueryError","info":"[V@1jogpAMD4AAGwCwuwAAABG] Database query error"}}

Console debug

[FLOW] apiRequest already in progress loadMoreTopics Array[3]
[FLOW] apiRequest already in progress loadMoreTopics Array[3]
[FLOW] apiRequest already in progress loadMoreTopics Array[3]
[FLOW] apiRequest already in progress loadMoreTopics Array[3]
[FLOW] apiRequest already in progress loadMoreTopics Array[3]
[FLOW] apiRequest already in progress loadMoreTopics Array[3]

• 0: jQuery.Event
• 1: Object
• 2: Object
• length: 3
• __proto__: Array