OSC indicates cached data with incorrect order of magnitude about mpv_thumbnail_script HOT 1 CLOSED

I can't confirm, as the original osc.lua dropped the cache size in January (although it was too late for 0.27.2).
I don't know what arguments you were using, but patched_osc.lua seems to be doing the right thing (cache-used is KiB).
The patched OSC is supposed to be a direct copy of the original, but with a few added hooks to render the thumbnails, so I'm not too eager to add specific fixes for old mpv versions. I haven't updated it in a year, but there hasn't been much changed either, other than dropping the cache size display.

In short, the issue can be considered outdated and if there was an error, it was likely from the original file (or from version mismatch etc). You can edit your copy of the script to display the cache size properly, although everything should be correct as-is.

from mpv_thumbnail_script.