Indeed. This was an amazingly useful plugin but it's not been behaving well lately so not used it much.
If anyone clever could fix it for the 2020s I'd donate for sure to that!
__________________ subproject FRs click here note: don't search for my pseudonym on the web. The "musicbynumbers" you find is not me or the name I use for my own music.
In the meanwhile, I found that Melda Production's MChannelMatrix, set in surround mode, can do mostly the same (not only it has the routing matrix, it also can set the volume for each routing).
Of course you also need to play with the plugin pins.