A licensee has reported that the Draw function in BatchedElements.cpp can set the OrthoZoomFactor (not a local variable) to 1.0f if Line.bScreenSpace is ever found to be false.
The line this can occur on
Engine\Source\Runtime\Engine\Private\BatchedElements.cpp Line #955
The licensee proposes using a local variable instead for this loop so that this does not affect the global variable.
This was present in 4.13 as well
Code Issue - N/A
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-42160 in the post.