<https://community.ultimaker.com/topic/19249-how-to-tell-when-the-ptfe-coupler-is-bad/>
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<https://community.ultimaker.com/topic/19249-how-to-tell-when-the-ptfe-coupler-is-bad/#comment-186726>
<https://community.ultimaker.com/topic/19249-how-to-tell-when-the-ptfe-coupler-is-bad/>