The phrase أَنْ يَكُونَ عَلَمًا is a key restriction.
ʿAbd Allāh can also be a proper name, yet because it is iḍāfa it does not follow the mazjī-compound rule here.
Baʿlabakk is both a proper name and a mazjī compound, and so is diptote.
Conclusion: Proper-name status alone, or merely having multiple parts, is insufficient for this specific cause.
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Diptote Causes — Compounding and Its Conditions
The phrase أَنْ يَكُونَ عَلَمًا is a key restriction.
ʿAbd Allāh can also be a proper name, yet because it is iḍāfa it does not follow the mazjī-compound rule here.
Baʿlabakk is both a proper name and a mazjī compound, and so is diptote.
Conclusion: Proper-name status alone, or merely having multiple parts, is insufficient for this specific cause.