Hi forum.

This bug: https://gitlab.com/inkscape/inbox/-/issues/10781#note_2026948033

The headline for this bug is not quite accurate in describing the bug - I saw that afterwards. Turns out what probably happens are the Layer dialog sometimes fail to sort sub layers in correct order, being triggered by moving objects up and down though layers.

How do you guys think I should go from this?

I'm not sure how font preview and layer dialog box are connected. I can do a try anyway.

[EDIT]

Ok, I gave a try (I changed from 100 to 150, then restarted Inkscape) - but did not changed the behavior of the Layer dialog box when moving objects through the stack of layers.

The fact that Maren commented on this bug report tells me that this is a legit issue. You have demostrated it on multiple versions, multiple operating systems and multiple computers. You even did a video demonstrating the issue. 

There are many reasons why a developer cannot replicate an issue AT FIRST. 
 

Keep trying! 

Thanks. I just did.

turns out that there was indeed a factor that was overlooked. The "Only show layers" setting must be turned ON in order for this bug to appear. I've simply being blind to this myself.

I added my comments. I hope I am correctly interpreting your behavior expectations.

I was able to replicate the issues with v1.4.2 with WIndows 11 using your sample file and the "Only show layers" settings of the Layers Dialog

BUT - It took this  blind senile old man to review your video a trillion times and at quarter speed. 

https://gitlab.com/inkscape/inbox/-/issues/10781#note_2510796950

There is some additional info that I added in a followup message that demonstrates a very bizarre interaction with the Layer Dialog being open and active. 
Hopefully a developer will confirm it. Your report might also solve other bizarre issues with the layers dialog. 

added update to report