Bottled 2 batches of beer from kits and both came out with not enough carbonation . Used the priming sugar that came with kit. I have bottled same kits before n came out fine. Why ?
That sounds like long enough to carb for the first one at least.
What is the style of the beers? Some beers call for less carb.
Did you check the specific gravity before bottling? One comfort you can take is that the yeast was still active because they did partially carbonate.
Temperature of the storage area can effect processing time. I also recall that the temp of the beer at serving effects carbonation - I forget how.