I did the same upgrade to 7.11.12, with the same warnings in the logs.
JFrog support tells me that this is a known problem, does not affect anything, and is fixed in 7.117.x
I can't find the stated issue in the release notes, but we'll see when we upgrade to 7.117.x
As I have been burned by bleeding edge bugs in Artifactory before, I will wait with the 7.117.x upgrade until the next self-hosted version after that has been released.