Future doesn't adhere to masking-taped surface spots

That could very well be the problem Chris.

I tested with the same tape on a junk model with no problem.  As for the problem mentioned in my OP, I remember placing the tape on something to cut it in half.  Probably, the sticky part got contaminated.  If I need to cut the tape, I'll place it on a clean glass panel from now on.

Try washing the area with soap and water, blot dry and try again with the Future, I wonder if your tape was placed on a surface that contaminated the sticky part prior to putting on the model as when cutting a piece and putting it on my workbench edge to be used for masking. That is strange.

I too use Tamiya modelers masking tape that adheres both real and plastic surface and I am using it from long time but didn't face that problem.

http://www.snoick.com/