I wonder how this machine could ever have worked. Each sort of paper needs a different speed on my drum dryer, depending on weight and other material properties of the paper base. I don't think that the emulsion is that critical and I got good results with MG FB as well. But I have to admit that the older ORWO and Brovira, which I still have, are more trouble-free in this regard.

When I saw the picture of your machine, my first thought was: what a tiny little thing! My drum dryer weights more than 100kg (>220 lbs) and has a huge oil-filled drum that is back-heated (i.e. the paper gets heat from both sides). A small drum has necessarily more surface curvature which causes more tension to the emulsion. I've never used such a tiny drum dryer, but it seems logical to me that the more the paper is bent, the more likely the emulsion will crack.