MFXComboBox popup has height of 2.0

[elfoxus]

Describe the bug
I'm using simple MFXComboBox. Nothing fancy. Basic usage. Sometimes the first render of openeded popup has wrong size. Have anyone had similar situation?

Here I attach image from debugger. As you can see container in MFXPopupSkin has height of 2.

(that's the MFXPopupSkin method)

What I do is I have MFXStageDialog where I have MFXComboBox. Then sometimes on first opening(sometimes later) height is 2.0.
When I set autohide to false and change system focus to another application popup height is recalculated to expected target height.
What I noticed is that prefHeight of SimpleVirtualFlow is changing. I'm trying to debug the code. If I find any bug I will report it, for now just asking for any similar observations on your side.

To Reproduce
Steps to reproduce the behavior:

1. Open MFXComboBox popup?

Expected behavior
Height is always the same?

Screenshots

Here I attach what I see when the popup is renedered with bad height:

[palexdev]

I think I'll need a MRE because I can't reproduce it: