I've been using a command block (and comparator) to test for a player within the radius of a certain block to open/close a hidden door on approach.

/testfor @p[x=184,y=66,z=330,r=3]

The above was working in 1.9.4...but with the update to 1.10 it is broken. At first it simply gave an error message "entity UUID is invalid" etc. etc., then by (experimenting) eliminating the " = " 's the command executed but seems to completely ignore the coordinates, finding me anywhere.(have tried and tested with both redstone clock version and auto/repeat)

What has changed/am I doing wrong? Is there a working command for this, or is it truly broken?