question about mali half hardware standard

I read in wiki that ARM has a unique half precision standard and i want to know whether it's also true for mobile GPU like mali. I asked this because i do encounter a wired issue about half precision where same shade program with same data end with different result in different mobile gpu. The number i calculate in shader will be out of half precision range so it was supposed to be a NaN but instead its final output is NOT in some mali GPU while(i said some not all, cause in Mali-T830 the result is the same as other mobile gpu like in adreno or powervr while in Mali-G76, the result is different) . And i just curious whether it is related the ARM half standard I mentioned about. In wiki, it said"ARM alternative half-precision[edit]

ARM processors support (via a floating point control register bit) an "alternative half-precision" format, which does away with the special case for an exponent value of 31 (11111₂).^[9] It is almost identical to the IEEE format, but there is no encoding for infinity or NaNs; instead, an exponent of 31 encodes normalized numbers in the range 65536 to 131008.

"(arm community warn me that i shouldn't put link in my post so i just paste the content here, just google "Half-precision floating-point format  wiki" and you will find the original post)