Issues with VS Code

I've just started using VS Code as an IDE for Bash scripts and I'm having some rather irritating issues. These issue are seen under Kubuntu 19.10, Ubuntu 18.04, and Fedora 31, but none of these issues are seen under Windows 10 or CentOS 7.6 with the same exact script, extensions and settings (sync'd via Settings Sync).

I have the following extension installed (among others, but these seem to be the ones that affect me):

Bash Debug from rogalmic, version 0.3.6

Bash IDE from Mads Hartmann version 1.3.3 (bash-language-server is installed but not the Docker container for explainshell)

The issues I'm seeing:

If I type something that is not (yet) completely correct, such as typing the word "if" on a line, the entire file gets red squiggly underlines. Damned annoying, and not at all helpful.

The auto-complete does not seem to understand Bash at all. I type "if foo ; then" and hit Enter, and the word "then" gets changed to "gdk-pixbuf-thumbnailer".

I started trying different version of each and found that Code 1.31.1 and Bash IDE 1.3.0 are the newest ones that don't show the issues on Kubuntu 19.10.

VS Code   Bash IDE  Result
1.40.2    1.3.3     BAD
1.31.1    1.3.3     BAD
1.31.1    1.1.1     OK
1.31.1    1.2.0     OK
1.31.1    1.3.0     OK
1.31.1    1.3.2     BAD
1.31.1    1.3.1     BAD
1.31.1    1.3.0     OK (Confirmed)
1.32.3    1.3.0     BAD
1.32.2    1.3.0     BAD
1.32.1    1.3.0     BAD