What you're experiencing is pretty common. Masking tape can be murder on a lacquer finish. If it were simply tape residue it would be no problem. In that case lighter fluid, naptha, anything like that would work. But I believe in your situation the adhesive on the tape has reacted with the lacquer itself, leaving a foot print that has marred the surface of the lacquer. Lacquer and blue tape don't mix! Especially with the rattle can lacquers, that stuff is just too soft. Even with the instrument lacquers I use, if I have to mask off an area I will leave the tape on for no more than five minutes. Any longer than that and it will likely leave a foot print. No big deal if you are planning to buff out anyway, but it still requires wet sanding. There are different kinds of frisket films available that may be more suited to masking the bridge area. I have yet to try them but they sound like they would work because they are a lot less tacky.
The other problem with lacquers like Deft is that they can pick up an impression from the case strap. One time I did a monthly workshop with about 25 students and because time was a factor I had them shoot Deft on their ukuleles. After hanging for a month they were finished and put in their cases (the foam core zippered ones) where they sat for another month until they were delivered to the charity they were going to. The night before they were to be delivered I noticed that 75% of the ukes had strap impressions left on the lower bouts. I cut all the straps off the cases and spent the rest of the night buffing those impressions out.
Deft, Watco, or any of those home improvement type sprays really shouldn't be used on an instrument IMO. It stays soft forever.