This MIGHT be the ONLY monitor with which this newer svideo mod causes trouble, but untill I'm 100% sure of this, I won't take any chances modding systems for others without adding a composite/svideo switch.
I don't blame you on that, but I did read that others had issues with SD content on that monitor in regards to picture quality leaving a lot to be desired. It's pretty much a given that its chips handling the analog SD contents processing is subpar. As with any older cheaper to medium priced LCD monitor, this can happen. Everything analog SD wise is handled with a lot of processing compared to a SD CRT tv, so skimp on the tv cost, risk having issues. I waited until 2010 before I bought my Toshiba, and I only did it after looking up tons of reviews for its SD support, which ended up being rather highly regarded. I paid almost $500 for mine, but it gives good results. I am just at that point anymore where I don't want to run 8 to 16-bit stuff on it anymore. I have become spoiled.
Like I said, if anyone else is having the same or similar issue, would be helpful to have it posted on here, and to have their monitor model and type and year make listed. I would be really curious to see if it is happening to others if it is only related to LCD type monitors and if so, if it is just older types. Also just to state, I don't think the people who developed this mod had any intentions for others to just use it to mod other peoples systems for profit, nor did I provide the original post easy to read one for this purpose. Unless you have access to quite a few SD and HD tvs for testing (like me) then you have no business doing it for others for pay either.