Scripting command that switches expression engine doesn't seem to "take"

This bug report is in reference to the thread here: https://community.adobe.com/t5/after-effects-discussions/script-that-switches-expression-engine/m-p/13995215#M234286

I have a script that requires the Javascript expression engine because of text styles, so I added this code

var projectEngine = app.project.expressionEngine;
if(projectEngine == "extendscript") {
  alert("Wrong expression engine, blah blah");
  app.project.expressionEngine = "javascript-1.0";
  return false;
}

It successfully changes the expression engine, but the expressions that get added by my script still show errors saying "property or method named 'style' is missing or doesn't exist." This happens for every additional expressions added by my script. If I manually open the project settings window, it shows that it has been changed to Javascript, and even if I don't change any settings, clicking "okay" fixes the broken expressions. They stay broken until I either check the project settings or save, close, and reopen After Effects.

Tested in:
After Effects v22.2.1 (Build 3) on macOS v11.6.5
AE v17.7.0 (Build 45) on Windows 10 Pro build 19045.3208
AE v23.4.0 (Build 53) on Windows Server 2019 build 17763.4499

Please let me know if you need more info. Thank you for your time.