I recommend shellcheck as well. It might not catch your problem, but it will point out possible problems.

Also I recommend: rewriting scripts in another language. At work we are converting bash scripts to rust and while it’s a high ramp-up time, the resulting code is much easier to maintain and I have a much higher level of confidence in them. Bash is still good for quick scripts but once you hit 100 lines or so you really deserve a language with stronger guarantees.