Logo changes size while hover (only Firefox)

Hey! I use the Pique theme and just discovered something weird.
When i hover the logo it gets really small but only in Firefox (newest version).
In Edge and Chrome it stays the same size.

I checked if i have the problem in the official live demo. There the problem doesn’t exist.

I checked if the problem occurs in one of the wordpress standard themes. It doesn’t.

I deactivated all plugins but the problem still exists.

Then i searched for some code in the style.css of the pique theme which maybe makes this problem. It is this part which starts in line 880:

.site-branding .site-logo-link:hover {
	-webkit-transform: scale(5%);
	    -ms-transform: scale(5%);
	        transform: scale(5%);
}

When i delete this part, the problem doesn′t exist anymore.

I also tried it in a totally new wordpress installation which i have on my local computer. I can see the same problem and solution there.

Can someone check if they have the same problem?

Thanks a lot!

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