I had the same probs. They are good, they just ash funky and have a horrible after taste, even if they are FULLY lit.
yup, with coconut coals, you have to flip 'em like ya just did.
Last but not least...These things EXPLODE! You guys have NOOO idea on how many small, black spots I have all over the "hookah towel" I put under my hookah during smoking. These just happened because:
1. If you squeeze your tongs too hard while its holding cocos, embers go everywhere.
2. You barely blow on the coals to get them red hot and sparks go everywhere.
What you just described is what coconaras usually do imo. You did not get a bad batch, they are just like that