the bandaid tase typicaly come from 2 sources - a particular infection or bleach. In your case i would guess its bleach because some bottles have it, some dont. if you beer was infected i would guess that all the bottles would taste bad.
For a long time i had just thought it came from infection but i had a couple of batches that had the same symptoms yours did, band-aid like flavor in most of the bottles.
Do you use bleach at any part in your cleaning of bottles? Its really hard to get that crap out. I used it to help clean the bottles after my first couple of cases. Now when i finish a bottle, i imediately rinse it with water and wash it, and let it drip dry. I use only star san before bottling to sanitize. Bleach doesnt come anywhere near my bottles anymore.