Activity Chaining - The amount of time between attended tasks exceeds the non-configurable limit of 10 minutes.

This is sort of a basic principle of Appian process models... but for clarity, an Attended Task is essentially anything that halts the process flow to wait for user input.  Apart from rare exceptions, this is almost always a User Input Task node (there are some other types that can have a form added, but this is rarely done and, IMHO, should be avoided).

You'd almost never encounter any condition when chaining tries to persist for that length of time and isn't broken anyway.  Certain node types (timers, rules, etc) automatically cause chaining to stop when encountered - so something that takes that length of time would be, for instance, a very load-intensive smart service node (document generation, or some other type thing that could take excessive amounts of time).  Generally this would be designed around, because from the user perspective, they'd be sitting there just looking at a loading screen when waiting on long-running process elements like that to complete, which is a horrible design.