ebuild.patches 1 sys-auth/skey/skey-1.1.5-r10.ebuild: PATCHES is not a bash array on line: 25 Using a non-array variable like PATCHES="patch" is perfectly legal in EAPI 6, so this warning should be removed.
Patch committed: https://gitweb.gentoo.org/proj/portage.git/commit/?id=f7d987866e6e41130fe8b4d9f2046eb5d200abe8
Fixed in 2.2.27.