https://steamcommunity.com/sharedfiles/filedetails/?id=3366487990
I think I ran into an edge case while testing functionality. I connected two Loaders together to a Constant Combinator, which broadcast 4 positive signals (as you can see in the screenshot). Both loaders were set to "set filters", and they set their signals correctly. When switching over to Split Lane, however, the game crashed and gave me that report. The Loader I changed disappeared just as the game paused for the crash report. There were two loaders side-to-side, but only one shows up in the screenshot.
I haven't stuck my nose into the lua, but I THINK is happening is that the Loader is still trying to set all four filters even in Split Lane mode (hence "ID 3" of what's supposed to be a two-item array). Maybe a weird interaction network signals circumventing your checks to ensure only 2 filters are set?