Board Thread:General Discussion/@comment-36535642-20201019120844/@comment-9605025-20201019181741

When you have mismatched tags, the software attempts to be smart and determine where you meant to close it. This means that the HTML viewed by users is not a 1-for-1 translation of the bad markup. Instead, it is the bad markup with extra tags inserted by the software which can potentially dramatically impact the resulting page structure. Did you forget the closing div tag in the left column or did you intend to put the so-called right column in the left columns as well? The software has to guess. UCP seems to be less capable of handling mismatched tags compared to legacy.