Don't assume cause and effect. Call in a stucco specialist. If the pipe was always in that location, it likely is not the issue. That leaves water infiltration from other source.

If pipe placement is new, and is the issue, the cure is not simple or cheap. That's a complete redo.

Not enough information given to be able to offer an opinion.

More info on scope of work and pix needed.

This is a photo of the external linear bulge. Stud finder positive all along the line. Bulge looks like something white, like PVC pipe might be behind it. Crack is an inch or so from where new copper shower pipe is on the inside. Wonder if this should be investigated from the outside so we don’t have to destroy the brand new tile inside. Plumber coming this week to finish installing fixtures, so will ask him if he can tell what the problem is.

This is photo from indoors, new bathroom renovation. Tub to shower conversion. External stucco has a linear crack/bulge about 1 inch from new copper shower pipe. New cement board and waterproofing all around, new tile all around. 2nd photo shows crack in stucco. Plumber will finish installing faucets this week, maybe he will know what happened. Contractor is denying responsibility. We are thinking of getting stucco repaired independently of contractor, investigate crack by opening from outside, subtract bill from what we owe contractor.

Going to guess that the stud wasn't properly nailed dating back to the original construction or has since split where it was nailed into the plates. Somewhere along the line in the remodel--during demo or installation of the tile backer board or drywall, some considerable force on the stud moved it out of position and caused the crack/ bulge.

Or possibly a new stud was installed (if this was a gut job) because a nailer was needed in that spot.

May or may not have been the contractor's fault.