WUR influence @ full operating temp

[930turbo]

Does the WUR have any influence on the mixture @ full operating temperature? In other words, does the bi-metal spring come completely off the control pressure springs once it's hot? Or, does the bi-metal always play a part in mixture control regardless of temperature?

[RarlyL8]

The bi-metal strip stops moving at normal engine operating temperature once the temperature at the WUR has equilibrated. If the temperature at the WUR is further increased or decreased the bi-metal strip will move accordingly.
To directly answer your question, I do not know if the bi-metal strip ever unseats itself. I doubt it due to the mechanical function it performs. The bi-metal strip has a range of motion that diminishes at the extremes. That range of motion is compromised with age, one reason why aging WURs go off-spec on their own, usually first seen as a lean cold start and the classic "chugging" at low idle.