An issue existed in the selection of video file by Mail. The issue was fixed by selecting the latest version of a video. This issue is fixed in iOS 13.4 and iPadOS 13.4. Cropped videos may not be shared properly via Mail.
Apple Security Advisory 2020-03-24-1 - iOS 13.4 and iPadOS 13.4 are now available and address buffer overflow, code execution, and cross site scripting vulnerabilities.