Video thumbnails aren't generated/shown for Android if uploaded from desktop client

I don't see an "issues" section for the desktop client so I'm posting here. Basically, when I upload a video from the Android client, it generates a thumbnail so that it is displayed in the chat. When uploading a video from the desktop client (same type of MP4 video), no thumbnail is created and it displays a generic black box (with play button) on the Android chat stream.

Steps to reproduce the behavior:
1. Go to Element desktop client
2. Upload a video
3. View chat/video on Android client
4. Thumbnail of video is not shown (black box with play button)

**Expected behavior**
I expected for the video thumbnail to show, as is the behavior when uploading from the Android client

**Screenshots**

Desktop:

Android:

**Smartphone (please complete the following information):**
- Multiple variations of android with fine in this case, the issue is the desktop client video upload

**Additional context**
- My instance is Synapse 1.25 installed via Docker on Ubuntu 18.04