That's not how it works Brian, ticking the box will cause Lightroom to automatically remove CA, you have no control over what it does. You can manually select the defringe tool regardless of whether the box is tciked and select specific fringes, this works in addition to whatever it's done with the box ticked. This bit can work fairly well as it just desaturates the colour chosen and the sliders control how big an area it targets. Sadly it usually brings up an error if you try and use this to attack regular lateral CA as it's the wrong colour.
Unfortunately (or fortunately) very few of my images seem to suffer any CA, and I cannot find any with such chronic CA that cannot be removed automatically by ticking the "Remove CA" box.
If I try using the manual controls then they do just as good a job.
I have never encountered any error messages when using the manual correction tool.
As for the CA being the "wrong colour" surely that's why you use the manual tool, so you can select the colour you want to neutralise?
I'm afraid I'm not familiar with the expression "bokeh fringing" so I can't offer any assistance with that.
In my workflow, Lens Corrections (along with CA removal) is the first step in my processing, and I tend to click both boxes automatically, often whether they are needed or not.
Are you attempting to remove CA from a processed image? In which case it may be worth changing or reviewing your workflow to process CA at an earlier stage?
Personally, I think the concept of one click software CA removal is pretty amazing in itself, and I'm sure that software programmers from a few years ago only dreamed of such automation.
Hats off the the Adobe programmers for incorporating such an innovation which, for me, does exactly what is intended.
Obviously everything has it's limitations and one cannot expect miracles, but it sounds like you are exceeding the capabilities of LR in this aspect.
Maybe future editions of LR will offer enhanced CA removal tools, but since I only use LR for my raw processing, I'm afraid I do not know of any alternative programs that may be able to do what you are attempting.