Highlighting a video file in Windows causes very high disk activity

I'm using Windows 7, and when I highlight a video I noticed it takes a few seconds for the thumbnail to load. So I then checked the Resource Monitor while doing so and noticed the disk activity jump to around 400 MB/sec. After the disk activity drops back down, the thumbnail finally loads. If I click away from the video and then highlight it again, it tries to generate the thumbnail again.

Here's the thing, this issue is happening only on my TV captured files (.TS) that are a few GBs (3-5) in size. I tested this on other LARGE video (non-tv captured) files that are mostly .MP4 and .TS that I have on my computer, and there's maybe a couple hundred KB/sec (KILOBYTES/sec) of activity, which seems should be the normal.

Is there a change to how it generates the thumbnails in a more recent version of the (Klite) codec pack? I don't regularly update it, but I did notice this behavior when I reformatted and reinstalled Windows and newest version of the codec pack.

Is this a bug with the program, or my recordings?

It might actually be the file property handling of Windows that is being slow. I have seen that happen before with such files. You can test by disabling thumbnails with the Codec Tweak Tool.

Otherwise it would also be slow without highlighting the file.