I reported this, too, but nobody cares it seems. Happens in songs, too, somewhere, I guess inside instruments.
There is little point with backwards compatibility if it’s full of bugs like these. I already posted another one concerning the old ringmod too,https://forum.renoise.com/t/old-ringmod-device-randomly-breaks-after-a-while/45873 . Soon none of my old instruments work as they should. 