Flat beer- too much yeast?

Been brewing for just a year. I brewed a Chimay Grande Reserve clone this summer. Starting to drink the fruits of my labor now (can't wait longer) and noting that 1/2 the bottles I open are nicely carbonated, 1/2 are flat flat flat with no carbonation at all. In the recipe it said to "prime the beer in the secondary with another dose of the same strain of fresh yeast" 3 days before bottling. So I dumped another 4 oz. bag of Wyeast Belgian Abbey Ale yeast in the 5-gal carboy and then bottled a week later.

Anyways...general question...any ideas why 1/2 my bottles would be flat and 1/2 are actually pretty good? Thanks.

inconsistent carbonation between bottles is usually due to an uneven mix of the priming sugar during bottling.

Got it...Thanks!

Or possibly a problem with the caps.

If the sugar was added individually to each bottle it sure could be that. If the sugar was bulk added (which is really the way to go with bottle conditioning) then I definitely vote for the caps being the culprit.

Priming sugar was bulk-added. I brewed and bottled this batch by myself (usually there is a group of us doing it), and now that I think of it, the bottling part was a bit of a fiasco. I was hurrying to get the caps on, and I bet I'm paying for it now.

Going forward, for the ones that I open that end up being flat...Could I just add some more priming sugar to that bottle and re-cap (slower this time)?