For what it's worth, Apple are just conforming to the JEITA/CIPA DCF standard: https://en.wikipedia.org/wiki/Design_rule_for_Camera_File_sy...
“DCF file names” specification sez… http://www.kronometric.org/phot/std/DC-009-2010_E.pdf#page=2...
“File names conforming to the following rules are called DCF file names.
• The file name is 8 characters (not including the file extension).
• The first four characters consist only of the upper-case alphanumeric characters shown in Table 1
• These are referred to as the DCF file name Free characters. They shall not contain two-byte characters or special codes.
• The four characters that follow are a number between "0001" and "9999". "0000" shall not be used. These four digits are referred to as File number.
• Files with the same file number stored in the same DCF directory are considered to be object component files as defined in 4.3.2.”
The issue stems from the fact that images are written with proper EXIF time and timezone metadata while videos from the same camera might only store a timestamp field. Whether that's local time, UTC, or something else depends on the camera and how you configured it.