I recently put together a parts bass, HWY1 p-bass body, fretless MIM jazz neck and tuners with a 62 pickup. It sounds phenomenal and holds tune for the most part. My band has one song that the guitarists both capo at 2 for, and the last 3 or 4 times we've played it, I've noticed I was off by almost exactly 1/2 step on the A and E strings, so I'll correct my playing to match sonically. At first I thought it was just the capos on the guitars throwing them off, but I decided at our last rehearsal to actually tune after the song, lo and behold I was exactly 1/2 step flat on those two strings, with the G and D strings still being right on. I'm planning on upgrading the tuners to some ultralights as soon as fortune smiles on me a bit, but for the life of me I can't figure out what is causing it to be thrown off at that exact time. I do use a bit of vibrato on the A string during the song that could account for that string going out, but I play pretty straight on the E, and usually use slide vibrato instead of bend-vibrato. Any insight?