The corruption icons does not show when using the TBag bag addon: https://www.curseforge.com/wow/addons/tbag-gagstv.

As you can see I have enabled it in the options: https://i.imgur.com/QkjCweq.png

For any bag addons, if they don't just simply extend/coorce the default bags to do what they do, you must create a patch for them, I've completed this for Adibags, Bagnon, ArkInventory and ElvUI. The same would be needed here.

I took a quick look, and there doesn't initially seem to be a hookable function that I can use when it's drawing it's bag frames. Given that its a very little used addon, and appears to be unmaintained on master, left to a fork, I think this is beyond me. But I'll keep the ticket open incase anyone wants to pick it up.