I’ve only looked at this in Apple Mail on macOS High Sierra and iOS but the invite has a rendering issue on macOS. There, the length of the url seems to shift everything to the right edge of the window. The email looks fine on iOS.
Additionally, a minor thing but I’m a — the profile photo is left-aligned on both macOS and iOS which may be intentional but since the rest of the content is centered it feels like the photo should be centered as well.
I did some testing on this end and there are some definite inconsistencies with accessing a content editor invite email in a browser vs the MacOS Mail app.
I’ve alerted the team of these and we’ll work on a fix – thanks for the feedback here!