But, and this is the important part: depending on how the company is structured, reporting a bug in a closed source project will result in unplanned work. If the company takes a "everyone is responsible for all bugs, we don't assign blame" then it is likely someone will report it.
If the company, whether explicitly or implicitly, is communicating that if you report the bug, you fix it, then there is a good chance you will not report it, if you own it.
If you own something, you can be fired if you break it. So there is a perverse incentive to not report your own bugs, especially if you inherit a mess.