Lens Correction - auto profile adjustment paste issues

I am having issues with LR (15.0.1) behavior when applying auto profile lens corrections (via copy/pasting, "paste from previous," or creating/applying a preset).

As soon as I reduce the "amount" of distortion or vignetting, the profile setup gets changed to "Custom" and as such copy/pasting applies the exact lens profile (the model & profile of the copied image) to the next image regardless of whether it used that lens or not.

My usage case is something like the following:

1) I have pictures taken on a Canon EF16-35mm f2.8, as well as pictures taken on a Canon EF35mm f1.4 and a Canon EF50mm f1.4.

2) Often when I click "Enable Profile Corrections," I like to turn the distortion correction to "0", and reduce the vignetting correction to 50.

3) When I proceed to the next image and paste from previous, LR also applies the Lens corrections with the lens profile & model of the previous image. The can be quite frustrating, as any change of lens means I have to avoid copy/pasting settings from a previous image. It's often hard to catch & I end up applying the lens profile of the previous image to the new one.

This behavior occurs when using copy/paste, paste from previous, as well as creating/applying a preset with the lens corrections included.

The exception to this behavior, is if I highlight the whole session and use Autosync. If I first apply "Enable Profile Corrections", then turn off the distortion and turn down the vignetting, Canon respects the lens profile of the lens used to take the image for all the adjustments.

I would be interested to know from others whether this is expected, helpful behavior, or whether they would consider this a bug.

I would also love to know if there is any workaround. For me, so long as I have adjusted the distortion or vignetting of the profile correction, I have problems editing, because the profile correction of the wrong lens keeps getting applied to subsequent images when pasting from previous.