In general; it is perfectly normal to have to configure Autoptimize to exclude some JavaScript. Given the complexity of cross browser support for JS, it is also possible everything works perfectly in modern browsers, but dinosaur-browsers require some extra configuration as well.
Now it's hard to tell without being able to see the actual error, but in general when using jquery (as on those sites) you'll often have to configure Autoptimize to exclude jquery.js from javascript optimization. In your case you might have to exclude jquery.royalslider.min.js as well.
Some more trial & error might be required, but -in my opinion- the performance gains is worth the effort ;-)
hope this helps,
frank