At your earliest opportunity check the torque of these bolts. Have experienced loosening of the bolted joint due to compression of the fiberglass over time. The plates are installed to increase the clamping surface area and to minimize compression of the fiberglass material. Last project where I witnessed issues with Cofimco blades the bolts started to snap, fiberglass cracked as you are experiencing, bolts fell out, etc. Had to replace/rebuild the affected fan blades and retorque others. Cofimco increased the bolt torque value for this particular unit.