Howdy, @scotbaston!
Thanks for writing in and sorry to hear that you seem to be experiencing an issue with this. Upon review of the situation at hand, I believe this is likely due to some custom CSS you have at play on your page and does not lie with the v2 buttons or columns.
I can indeed see the issue of the columns not flowing properly in Safari when viewing your link, but when replicating this exact setup on a local installation and then viewing it in Safari, I am unable to reproduce this same issue. I have setup my own page in a local environment using a four column layout, then setup a Button Element in each of those just as you have (column flexbox layout for content, image up top, text below, border included, et cetera), and when I view that test page in Safari, I do not see the layout issue that is present on your page. Below is a screenshot showing my test in Safari and that the columns are not breaking as they are with your home page:

Regretfully, I’m unable to ascertain the exact source of what I believe to be the issue on your page, but I do see that you have some custom CSS going on, and more specifically on your buttons with the .hover_sheen
class. Please test removing all of your custom CSS for a time to see if that remedies the issue, and then from there you can work to narrow down to the problem source (which I believe to likely be the class mentioned previously). Since this is related to a personal customization, you will need to work through it and try some alternatives to see how to resolve it.
Hopefully that helps to point you in the right direction.