I'd worry about cracked wheel bolts. Once you get movement like that, it's easy to fatigue the bolts. Below is an example of a wheel hub unit where the lugs were loose.

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Even if I've just replaced three of the lug nuts?

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Black '03 SLK32 AMG

The remaining two took up the slack in load. Plus there was movement. Every text book mentions that fastener fatigue can only happen when there is movement within the clamped assembly. With fatigue you get no deformation of the part, so there is no gross warning of the failure. Only a close inspection can tell you if the remaining wheel bolts have fatigue cracks.

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95 E320 Cabriolet, 169K

On Mercedes (and many other cars) the lug bolt is a separate piece that threads into the hub through the wheel, not like in the picture you posted, even if the original bolts were somehow fatigued the three replacements would not have been which makes that an unlikely problem. at mrgpep I would just check them once a week for now to make sure this is just an isolated incident, it is not uncommon to have to re tighten after that many miles but if you keep finding them loose every week or two then the hub may have stretched or stripped threads (which is pretty unlikely since the bolts themselves are designed to be weaker than the hub)

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E30 B25
126.036
123.130 with 616-Frankenbenz (sold)
124.030-Greyhound (sold)
124.030-Schnauzer (sold)

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