Screen position out of view frustum - is this caused by Cinemachine?

I'm using a Cinemachine camera as my main camera (well, the Brain is on my main camera but I'm using a CinemachineVirtualCamera as a Follow Camera). I have a typical UI Canvas in Screen Space - Overlay mode.

When editing the Canvas in 2D mode I'm getting the following errors spammed into the Console repeatedly:

Screen position out of view frustum (screen pos 256.000000, 0.000000, 1566152.250000) (Camera rect 0 0 256 256)

These seem to be coming from the function Camera::ScreenToWorldPoint.

If I zoom in enough so that the Z component of the screen pos is < 10,000, the errors go away, however I am so far zoomed into the scene that my UI is not visible because I'm only looking at a very tiny part of it.

So I have to be zoomed out to about Z=130,000 to see my UI full-screen in the Scene view.

I'm not entirely sure this is related to Cinemachine but I can't find any resolution to this so I'm wondering if anyone here might know how to solve this problem?

I'm using Unity 2020.2.2 and Cinemachine 2.7.3.

 

Thank you for responding, Gregoryl. Sorry for the delay in responding, I didn't have email notifications enabled (EDIT: turns out I did but the email ended up in another folder - never mind).

Well, I only have to move my camera in the Editor, and hitting 'F' moves it to the necessary location, it just happens to be 130,000 units on Z.

Here's my vcam inspector:


Also, my main camera:


I'm a bit suspicious of that "Aim" = "Composer" warning - I don't think that was an issue with Unity 2018, I think it only occurred after I upgraded to 2019 or maybe 2020 a little after that, but this Screen Position issue is a lot newer than that, I think. Just saying it might be a red herring, but if you think it might be a cause please let me know (I've updated from 2018 to 2019 to 2020 in the last ~4 months).

For context, the cameras are on a "Core" object which is at scene root:


Here's my Canvas inspector (Canvas object is also a direct child of "Core"):

 

Do you have any idea why this canvas is so large? Is that just how things are?

Thanks for the tip about the warning - I'll do that provided I can still set the Lookahead, Dead Zone etc. I'm using "Follow" but not "Look At" - I assume it'll still look at the thing it's following? This is something that changed after Unity 2018 and I was never sure how to update it.

 

In case it helps anyone else, I finally figured out what was causing the "Screen position out of view frustum" error in my original question - it only happens when I'm in "2D" scene mode, and it was the use of a Water plane (Water Pro Daytime from the Unity Standard Assets pack) directly perpendicular to this plane (i.e. perfectly level). If I disable the water, or rotate it a very slight amount (0.00001 degrees) around the X axis, the error ceases to appear.

So confirmed - nothing to do with Cinemachine. I appreciate that the Standard Assets are not technically supported by Unity 2020.x but I thought I'd report back anyway.