This is because pkgpaths differ from previous versions for both of them. >From pkg_add(1):
"To update packages in -u mode, pkg_add performs the following steps. [...] 4. Candidates are then matched according to their pkgpaths in order to weed out similar packages with distinct options." In addition to pkg_add(1), you can read OpenBSD::Intro(3p), the PACKAGE UPDATES section. I suppose something was done wrong during the port update. Also, do you have two libc versions installed or they are simply linked to them? -- caóc