Thanks for reporting this! I would expect it has to do with the flex implementation or something similar in said browser, provided that these .input-groups use this feature. However, this does not happen with aligned forms, as far as I can see, which might disprove my theory in the end. It's highly unlikely that something overrides the padding of the input fields so, if this is not a flexbox implementation bug, it might be a bug in the browser's implementation of input or similar. I'll google around to see if this has been reported anywhere else before, otherwise opening a SO question is our best bet to solve this.

Lately, I've been finding a lot of browser bugs that are specific to native browsers and I'm starting to believe that I will have to move away from Normalize and to something else that does actually provide a better documentation on how those are fixed.

Ok, it's here:
https://github.com/Chalarangelo/mini.css/blob/master/src/mini/_input_control.scss#L115

I think the Samsung browser is interpreting flex-basis: 0 to set the initial width and height of the element to 0 and then nothing ever gives it any height except the border and the padding. My flexbox skills only go as far as flexbox froggy, so I'm not sure what the ultimate solution is. However, flex-basis: auto seemingly fixes it without any side effects for my case.

Will test and, if I don't find any issues with it, I will apply flex-basis: auto as suggested I don't see anything that can actually go wrong, but I need to make sure. I'll keep you posted!

Ok. Thanks a lot! I'm working it around it pretty easily now, so no worries if you can't fix it. I'm guessing it's an old Chromium bug when Samsung forked that they never patched.

This has been addressed in #83 with a quick and simple fix. Just update to the latest version (I will release it in a little bit) and you shall be good to go!