Ok, but I want that feature turned on for all of the other nodes in my diagram.
Unfortunately, that feature is not able to differentiate between types of nodes. It is either all or nothing. You will have to temporarily turn off "Dynamically Adjust Node Size to Label Size" before editng table texts.
What I believe is a bug is that the lane widths change when changing the table title text.
Since changing the table text also resizes the table, there is no way to keep all lane widths the same. Resizing a table will always result in changed lane widths. Actually, this is the same point as the previous one: You do not want "Dynamically Adjust Node Size to Label Size" to affect table nodes. Unfortunately, that feature is not sophisticated enough.
It would be ok if the resizing of the table actually respected the content of the table but it does not and this results in table content changing lanes when changing the table title.
I will admit I am surprised that the first column actually inceases in width. I would have thought all columns shrink somewhat. I have filed a request for improvement for that one, but I cannot promise when or even if we will be able to work on this.