System Information
Win 7 Home - 64 bit, GTX 580
Win 10 Home - 64 bit, GT 730
Blender Version
confirmed 2.77 438bdcc and 2.77a abf6f08
Short description of error
Using tool_settings.use_mesh_automerge causes selection issues, specifically in edge select mode, with two or more consecutive/parallel loops selected. Blender will select ring edges after transform operations. See: Imgur
Exact steps for others to reproduce the error
New scene > Subdivide default cube > Select two or more loops (should be parallel, should not be separated by another loop) > G/R/S/etc the selection > Note selection has been extended as if changed to vert mode and back.