I careful analyze different scenarios for the QCD axion to determine the real chances that the single microlensing candidate detected by the Subaru HSC survey is sourced by Bose-Einstein Condensates (BECs) of QCD axion. Such astrophysical objects are known as axion stars or axion clumps and may compose today a sizeable fraction of the dark matter in galactic halos. Depending on the Peccei-Quinn symmetry breaking scale versus the scale of inflation and the details of the dark matter scenario under study, QCD axion clumps may form via three main mechanisms: thermalization and gravitational condensation during radiation domination, nucleation in the dense core of axion miniclusters, or nucleation within ultracompact minihalos around primordial black holes. Considering aspects such as axion clump masses and source magnifications, I conclude that the microlensing candidate found in the Subaru HSC data is likely not caused by QCD axion stars in standard cosmologies. This talk is based on arXiv:2109.13153 [hep-ph] (accepted for publication in PRD).