Some HTM Files Created by Outlook 365 Change from En to Ch Character Set Upon Upload

[Tom Scott]

Just downloaded FZ 3.54.1 Prior to latter upload incident.
Very few HTM files created by Outlook 365 MSO 16.0.14026.20202 32bit with the Save As (to htm) have this issue.

Several messages were saved in this manner (htm) then uploaded using FZ. Only one message presented the corruption. But it did so repeatedly.

After the save-as the file displays properly locally.
However, it is converted from En to Chinese character set when uploaded.
Renaming the file to html has the same result.
However, if renamed to .zip, uploaded and renamed back on the server, the English char set is retained and the file displays properly.

Comparing the file sizes of one such corrupting file finds 69 bytes fewer in the corrupted file. I'm guessing those are CRs not stripped by FZ.

Most of the time this does not happen. Only some files. This has only happened twice. The latter time, it is believed that Word 365 (2016 or 2019 version) may have been the source prior to sending from the same version of Outlook. The recipient Outlook was the same each time.

Each time the problem presented, other files uploaded without issue. Uploading the corrupting file multiple times replicated the results.

The first time the issue presented, an earlier but recent version of FZ was used. At the time, it was suspected that the message sender may have been subject to malware. The file was discarded as it was not mission critical.

The problem is evident in several web browsers (IE, Edge, Opera, Chrome & FireFox) and viewing the uploaded text using Notepad++.