You can get paint pens that will make touching those areas up super easy.
When I've had paint do that at the edge of the tape, it's usually been from the paint going on wet and the solvents invading the edge of the tape and causing trouble. This is also why masking should typically be removed as soon as possible without damage to the newly sprayed paint. The harder the paint gets, the more likely the tape is to lift an edge or crack the paint or something.
