The bolt holes where the coil bracket mounts do penetrate through into the area where oil drains back to the crankcase. If bolts aren't in those holes a small leak can happen on occasion. It isn't pressurized oil, just gravity flow back to the oil pan. Either bolt the coil where it belongs or just plug up the holes with short bolts.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
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