readmore does not always save

I am trying your editor on a number of sites with mixed results on the readmore button. Often I will put the readmore in there with the button on the toolbar and it will show up but then when I save it and come back the readmore is gone. Is this a known issue? I am experiencing this on a couple of my sites and as your product is so new i am reluctant to fully adopt this component before the bugs are ironed out. Thanks!