What is the issue?
When using long words, or links within article blocks sitting side by side, text can be seen bleeding outside of the article or block container, like so:
Why does this happen?
It has been determined not to be a bug (by our team and other teams of software developers for email HTML tools) but is, in fact, a known behaviour with HTML. All email design tools are limited in the code they use to be widely accessible by email clients as possible.
The limited set provided by some email clients that will receive the email do not support the CSS directives that could be used to make the text "wrap" even if you don't use spaces.
How can I prevent this?
When encountered, replace your long word or adjust its place within the content. Very long words that can fill the 1 column space are not so frequent in the real world.
In plain terms, we would ask you to be cognizant of using extremely long words, and spacing, when placing content into the column blocks. A common issue with seeing this is with lengthy URL's or emails, a good strategy to avoid that is inserting a link attached to a single word in the content, like so:
Check out the supported CSS styling guide on our help center here for more resources on CSS support across the vast majority of email clients.