We have a four layer (FR-4) board with one ounce copper on all layers and a six-layer (FR-4) board with two ounce copper pwr and gnd planes and one ounce on other layers that have recently began developing opens at specific locations where the thermal spokes on the gnd plane attach to the barrel of the PTH or PTV.
Microsection show the breaks, and we're looking at some handling issues during assembly, but I think its likely a thermal issue during the solder process based mostly on the post I've seen here. We're seeking information from the assembly house, but don't have that yet. I don't think it's a design issue; the spokes are 15 mils wide.
What else in design or fabrication or assembly might might be causing the problem?
Any comments, suggestions, solutions or help would be appreciated?

Calvin Reynard
Securaplane Technologies
10800 N. Mavinee Dr.
Tucson, AZ 85737
                                
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