Because of the various suspension geometry just because a wheel is off the ground doesn't necessarily unload a ball joint, unfortunately. This was true for a traditional McPerson setup, but double wishbones or multilink suspensions don't necessarily have the same results, unfortunately making diagnosing "clunks" a little tougher.

Here's a video -> https://youtu.be/_guTE2ANcIg

Don't look at this specifics since this is a rear wheel in a prior version X5, but conceptually something similar could happen in the front suspension.

Perhaps other's can give you more detailed diagnostic instructions.

There's a couple of things worth checking:
1) the trust arm bushings are filled with hydraulic fluid so when they break (and they do) the leave traces of fluid behind. This could give you a clue
2) do you have Adaptive Suspension? Just recently someone was trying to diagnose a "clunk" in the front end and he was investigating a possible issue with the servo controlling the front sway bar.

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