Rotohead ,
I can bet you money the holes are good, I have seen this happen numerous times, not being a product issue. Don't know how you installed them, I have seen guys tighten the bolts with the blade grip arm not firmly seated to the blade grip. And you did correct by noticing and placing the correct bolts (length) in there correct positions. You would be surprised how many times that has happened. The aluminum is soft however not to a fault. This is a critical step especially the installation and torque of the short fastner. You gotta know how tight is to tight and how loose is loose. You can ring one out easily. What was it like when you removed the fasteners to clean and locktite them in? I always make sure the grip arm is firmly seated and both fasteners are started (finger tight at the same time, not tightening one and then the other. Let me know if you need more help, PM me and I'll give you my cell number. And go over it in detail with you, also go over the rest of the machine if you have additional questions. Congrats on your purchase, you will love the N5c !!! Still my favorite heli.
K