Strange static over certain photos in project when rendered

When I render my video, some of the photographs are distorted. (see screenshot). It's not consistent throughout the video. I don't see this during the preview within After Effects, only when I render the file using Media Encoder.

I don't get any error messages.

This particular project includes several templates that we purchased from Envato. The person who worked on it originally (several years ago) never saw this. I was assigned to make a few changes and am now noticing the issues with the rendered file.

Output Settings

H.264 / High Quality 1080pHD

Software and System Info

After Effects CC: Version 15.1.2 (Build 69). I've installed the recent updates. It doesn't look like I can download version 16 yet.

Operating System and Hardware Info

Operating System: Windows 7 Professional, Version 6.1 (Build 7601: Service Pack 1)

Processor: Intel® Core™ i7-6500U CPU @ 2.50GHz (4 CPUs), ~2.5GHz

Memory: 16384MB RAM

No external drives

2 connected monitors - 1680 x 1050 (32 bit) (59Hz) / Intel® HD Graphics 520 / Approx. Total Memory: 4095 MB

Answers to Other Questions

1. What versions of drivers for your graphics hardware do you have installed (including CUDA driver and driver for display adapter)? I don't know
2. Do you have any third-party I/O hardware (e.g., AJA, Matrox, Blackmagic, MOTU)? No
3. Do you have QuickTime installed? No. I work for a state agency and would need to request a security review and special permission for this. It's possible though.
4. Do you have any third-party effects or codecs installed? I don't think so, but this particular project does include templates that we purchased from Envato.
5. Are you using OpenGL features in After Effects? I don't know

6. Are you using the ray-traced 3D renderer? I don't know what that is

7. Are you using Render Multiple Frames Simultaneously multiprocessing? I'm not sure