You'll notice
Bash command parsing now rejects unclear backtick or $() substitutions instead of guessing
What
The safety parser that analyzes bash commands before running them now specifically detects malformed or unaccounted-for backtick and $() command-substitution syntax, such as an empty or overrun backtick body, or an unsupported escape inside one. When it finds bytes in the command that its parse tree can't account for, it now downgrades the command to "too complex" instead of proceeding on a parse it can't fully trust.
Why
This closes a path where a command containing tricky or malformed substitution syntax could have been misread by the safety parser, by refusing to trust an uncertain parse rather than risk approving something incorrectly.