I'v taken a look at the website in question and I suspect the real issue comes from the website itself owing to the fact whoever created it is using CSS Styles which were deprecated a few years ago, and is also using <HTML> source code that does not meet the requirements for <HTML5> standards.
There is also some sloppy coding where closing tags do not match their opening tag.
Ultimately it will be up to web designers to get their act together and update sites, but for some clients the costs involved in doing this may be a barrier, although you'd think in this instance a site selling tickets would want to be using the correct source code given I'm assuming they want to stay in business.
Different browsers will handle poor source coding differently, but given Microsoft IE 11 and Edge are designed around HTML5 that would to me explain the anomalies you are seeing.
Edge will show that orange button - you can see it load as page opens, but as noted by the Opening Thread, it does disappear, and IE 11 will also display the orange button provided as Norton pointed out the Ignore colors specified on webpages under Internet Options > Accessibility is not checked in this case.
Microsoft Edge Internet settings are affected by accessing Internet Options, however, because its the new boy on the block per se, and the source code for the website in question simply is not good enough and no where near compatible with Microsoft Edge, the only real way to access this site using Microsoft's Edge browser would be to choose to open the site in Internet Explorer which can be done by selecting Edge's ellipsis . . . > Open with Internet Explorer
I do not currently have a copy of Mozilla browser handy so was unable to test that but can confirm Google Chrome also demonstrates display issues for this website, which do improve if you change the Internet Options > Accessibility as per IE 11 settings pane.