The question came up because I have a few plain vanilla JMs with thread grafts and on one of them all the grafts suddenly stopped extending. They put on a bunch of new nodes and then just stopped. No idea why this happened. All the JMs are basically the same size and age, and are treated the same way. And then last night I noticed that the grafts started to extend again. No idea why that happened either (although I am happy). So, any ideas why it would stop extending?