"Ship to a different address" Text Missing

The words “Ship to a different address” is missing from Firefox. I can see it in Chrome and Safari with no problem. I’ve tested this on 2 different computers with the same result. See the screenshot for what I’m experiencing.

It appears that the following folks have run into the same issue:

1) https://hb-themes.com/forum/all/topic/remove-square-and-widen-billing-text-boxes/
2) https://hb-themes.com/forum/all/topic/checkout-cart-chrome-firefox/
3) https://hb-themes.com/forum/all/topic/woocommerce-issues/

I tried adding the CSS code per #1 above, but no luck. I tried deactivating all of my plugins except for WooCommerce as per #2 above, but also no luck.