Error message
In the message, %s marks a value that the engine fills in when it raises the error.
The story
You wrapped a row that prints itself inside another row that prints, and the engine stopped you before it could happen twice. Here is the situation. The tui row already prints its own render when you call it on its own line. That is its job. Now, if you write the write builtin around it, the render would be printed by tui, and then printed again by write. The same picture, twice. The page for the row rules this as refused from the start, and the engine enforces it at parse time. So you never have to see double. The message shows you the nesting exactly as you wrote it, then gives the fix. Call the self printing row bare, on a line of its own. No wrapper needed. It is a little like telling a waiter to bring the dish, then also telling him to announce the dish: the announcement is already part of serving. Remove the outer write, run again, and the render appears once, cleanly.
Text from the Rush engine's error catalogue.