Simple query with Cacheable, Fetch and SingleOrDefault throws exception (regression from 3.3.0)

This is related to https://nhibernate.jira.com/browse/NH-3186. However if you say:

var query = db.Users
.Cacheable()
.Fetch(x => x.Role)
.Where(x => x.Name == "xxx")
.SingleOrDefault();

Then you get the same error thrown in the ticket above. I am currently upgrading from version 3.3.4 and this used to work fine.