When we tried to open a record that wasn't supported in Lightning, e.g. A google doc attached to a case or an idea record from a report, we used to get a nice message saying something like:

'This item is not available in Lightning Experience. Open this in Salesforce Classic'

It also contains a DIRECT LINK back to the record in Classic. 

Whilst we ultimately want everything supported in Lightning, this was a great workaround for our end users. 

Now we just get a blank screen when we try to open the record in Lightning. Not a great experience for our end users..... 

I have raised a support case around this, but can we please bring this back? I need this functionality for my users!!