Stress cracking of rims at the spoke holes is becoming more common on all wheels. This wasn't an issue years ago because rims were made of more ductile alloys, and builders used thinner spokes and lower tension.

Over the last few decades many have moved to thicker spokes and typical tensions have risen tremendously from what was considered proper in the past. Part of that is folks simply getting carried away, but also consider that modern wheels have more dish (asymmetry), causing greater tension differences between the right and left side (as yours does). Also, wheels with fewer spokes require more tension to compensate.

Years ago, the typical mode of failure in race wheels, was spoke breakage, these days rim failure is also common.

I don't know how many miles those wheels have, nor how heavy you are, but I'm not surprised about the cracks, and suggest you continue riding until they die, then replace or rebuild depending on the relative cost. If you replace, and want longer life expectancy, consider a wheel with more spokes.