Hi @DarcyIngold,
If a file is downloaded from Canvas, the "created" date shown in the operating system would generally be when the file was downloaded. That's just how operating systems (windows/mac/etc) and web browsers work, and Canvas has little control over it. With a word doc, once opened, the file properties area may show some additional info and dates, but some of those are also controlled by the operating system. I don't believe Canvas itself is really doing anything to the file, it's perhaps more a situation where users need to understand the information they are looking at and where it's coming from to ensure they are making correct decisions. This would really be more of a conversation you'd need to have with administration at your school/institution, at least that's my opinion.
I hope this info helps!
-Chris