Bug with ion-button on mobile Safari

Hello everyone, I’ve found something weird in my application and I wonder if anyone had similar issue.

When I enter screen that doesn’t have scrollable content I can normally see buttons:

But when I enter the same screen but with more content (I need to scroll down to see the buttons), they loose their background color:

After I click something, they are getting back the color:

Still hasn’t found any solution for that, has anyone experienced something similar?