The cursor options tailable and awaitData are documented as boolean but they are actually active if not null.
var cursor = find({},

);
is the same as
var cursor = find({},

);

I was exploring error handling behavior in a test and toggling awaitData from true to false had no effect. The mongodb module code checks if options.awaitData != null. Same thing with tailable.

Work around:
To turn these options off, you need to set them to null or not include them in your options object at all.