Borders Not showing up on my white buttons

I’m having trouble with buttons on my website.

I found this tutorial here No Matching Border for Transparent Buttons - it says borders around a button won’t show up if the button has a transparent background, but my buttons have a white background (#ffffff) so they’re not transparent.

I set up the buttons, they look fine. But then whenever I go back to the page, or I click on one of the buttons and go back to the page, the border vanishes.

Then I have to “reset” the border by changing it the type of border - ie it’s solid, so I change it to say dotted or double and save it, then the solid border comes back. But it vanishes again next time.
I’ve attached a screenshot of what they look like when I set them. I will post a second screenshot of what they look like no - the border has vanished in another reply

Here’s the screenshot of how they look now - borders are missing.