Soviet, Testing in Test Game can sometimes be a bit tricky.
From recent tests I have incounted that the media in mention can have major conflicts with the current and future versions and updates of this engine.
From my years of using this engine, I am not aware you can pin point the in question media you are trying to find. However bad news is the media/object/cutter may be imbedded so you cant see it at all.
I am currently in the process of building a 18level game, however I am planning on a new thread to help and explain how to over come errors such as these.
Also I should note, ButterFingers said this media is not supported. So its a risk and should be heavly tested prior to using in a prebuilt level.
Tips to try.
1. Revert back to a prior save of the level (if not, I suggest to to make these.)
2. Make a new level and place the in question media, to see what it looks like in editor (it may be a simple overlook)
3. Try to remember where you may have placed the in question media, and remove/delete all segs/entitys in this area and rebuild (make new save name)
4. Rebuild level over again, and test any unknown media in a new level before hand. (If it works fine, then its good to go)
Also on the topic, media that may have worked in a prior version and may now have conflicts with future versions, can cause many so called unknown errors. Search my profile, for a indepth find I discovered a few years back, it may help anyone understand lag/build errors.
I have attached a picture, this is the cause of a 2d array glitch caused by conflict media (in this case Butter Cutter), This is caused by a test build, recreating segment mesh underneath a prior segment.
more soon.....
demo released.