The phase precipitation, evolution, and transformation of the ${\mathrm{Zr}}_{41}{\mathrm{Ti}}_{14}{\mathrm{Cu}}_{12.5}{\mathrm{Ni}}_{10}{\mathrm{Be}}_{22.5}$ bulk amorphous alloy (BAA) are investigated upon prolonged annealing by means of in situ neutron diffraction, x-ray diffraction, and acoustic measurements. Icosahedral quasicrystalline (I phase), ${\mathrm{Be}}_{2}\mathrm{Zr}$ (hex, $a=0.38\mathrm{nm},$ $c=0.32\mathrm{nm}),$ and Laves phase ZrTiNi are observed at the first crystallization step. The I phase and ${\mathrm{Be}}_{2}\mathrm{Zr}$ phases transfer into stable crystalline phases at higher temperatures. The phase transitions induce marked microstructural and properties changes. The relation between the first precipitation of the temporary phases and the local microstructures of BAA is discussed. The precipitation of the I phase is suggested to be a structural heredity of the local icosahedral short-range order of BAA. The fundamental structural discontinuity between the crystalline and amorphous states results in an excellent glass forming ability and a high stability of the glass-forming alloy.