Mac OS X Mojave Heading dates wrong in Media Library or Import views

Since moving to Mojave, dates in the heading block in the media library or import views are incorrect. For example, media library shows first block as September 26 then next block as September 15, then Last Import, then September 25, then September 24, then September 27 ...

Import Selection shows November 13, then November 10, then November 13 (but not the same set of images), then September 13, (third time with yet another different set of images) etc.

This same behavior was observed a few years ago with a prior operating system update.

Am I missing something I should have done?