GiganticTurtle0 , let me add some background. The idea is that at some point you had your code running on your machine (when developing it for example),
when you actually executed the code itself in development, you call 'task.init' (to track the development process for example). This Task.init call, did the analysis of the code and python package dependencies and stored in on the Task. Then when you clone the Task, it already lists all the python packages your code directly imports (see "Installed Packages" section).
When the agent needs to run this Task, it will create a new venv, clone the code, apply uncommitted changes, and install all required packages as listed in the "Installed Packages"
The agent will also update back the Task on the Full (pip freeze) python packages installed inside this new venv, so it is later fully reproducible.
The caching mechanism basically skips the creation of the venv if the host (i.e. machine running the agent) already created the exact venv before (by default last 10 venvs are stored).

After all that background, back to the point at hand,

Yep, I've already unmarked the venv caching setting,

Just making sure, after unmarking it in the conf, did you restart the agent (i.e. stopped it and restarted it, the conf is loaded only when the process starts)

Maybe it has to do with the fact that I am not working on a Git repository and 

clearML

is not able to locate the 

requirements.txt

 file?

By default the agent will Only install what is listed in the "Installed packages" section of the Task (See Execution Tab -> Installed Packages).
If you press the "Clear" button (hover over the section to see it), and you clear the entire section, the agent will look for the "requirements.txt" inside the repository and use this one.

Does that make sense ?