The consistency of the bubbles in the left picture along with your description makes me think sanitation, too.
What did you use for bottles? How did you clean/sanitize them? I have found that Star-san by itself isn't enough to handle 50 bottles if I am starting with them labels-on.
What works best for me is to soak the bottles in PBW or OxiClean for a couple days to get the labels falling off or at least loosened up. Then, I hand peel all the labels off and scrub the glue residue off, and hit the inside with a bottle brush. At this point, I' used to just rinses with water and go into a Star-san solution, but I've found that that just doesn't have enough oomph to kill all the wild yeasts in the air here (which latches onto the bottle labels and glue) where I live. So, rather than straight to star-san, I hit them with a 5 minute soak in a bleach solution to kill everything off then its rinsed very well before finally going into a star-san bath before bottling. Iodophor would work well too.