Hi,
No it’s not a bug. Currently the plugin only works as a TinyMCE embedded plugin, in other words, you need to be in visual mode to have those buttons.
Since you are doing a log of editing in text edit mode, I suggest you go back to visual mode when you have finished editing, then select a whole bunch of text and go for automatic links addition (second button with double arrow). It is going to get the right meaning for you automatically. So it might even be faster.
Sorry for not replying sooner.