It should have been specified in the PO to be ground flush.  As you mentioned, it will cause problems with your automatic welding as well as your AUT.  I had that problem once before in Russia and we did grind the external seam.  Check with the welding & AUT equipment manufacturers for the positioning of their equipment relative to the weld and grind only back as far as needed.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website: www.oil-gas-consulting.com
 

Differing AUT equipment have differing footprints, which could be proportional to wall thickness dependening on the system to be used.

If the weld cap is not removed then the scanning probe pan is very likely to be knocked and damaged by the impact with the reinforcement. I have seen it where just a millimeter or two lip of remaining weld reinforcement has knocked probes off and twisted the mounts causing delays.

I agree with Greg - determine the AUT outfit's requirements and have the reinforcement ground flush in the pipeyard.

Nigel Armstrong
Lloyds Register
Independent Verification Body Surveyor
 

Specification normally ask for about 150mm of the weld bead will be ground with not more than 0.5mm projection.

Narendranath R
Pipeline engineering is made easy with state of the art computer software, visit www.narendranath.itgo.com.

Same thing happened to me on a project, and as the group above has stated... check the AUT and AWS equipment specs for cut back.  Grind flush and check the WT constantly throughout the process to make sure you do not undercut the line pipe.  This can be done for a cost at the coating facility prior to applying CWC.