Efflorescence in the joints (new construction)

Hello, unfortunately we have severe efflorescence in the joints.

Unfortunately, it rained immediately after grouting, causing the various substances to settle on the cement mortar like a salt layer. (see pictures).

Does anyone here know if the joints will eventually "wash out" again due to weathering, or is this rather a defect so that we need to ask the developer for remediation?

Thanks for responses