# Broken ValueQ function in Mma12.2?

f[x] ^= 1;
ValueQ[g[x]]


returns True in Mathematica 12.2. Is it a bug?

The behavior of ValueQ has changed in version 12.2. In fact, you can provide a Method -> "Legacy" option to match the behavior the function had in Version 12.1 and earlier:
The Details portion of the documentation for ValueQ now states that the default method in the 12.2 implementation (Automatic) effectively uses "OwnValuesPresent" if expr is a symbol and "SymbolDefinitionsPresent" otherwise (which means that "one or more symbols have any sort of definition present"). As I understand it, g[x] is not a symbol, so the latter is used.