There is currently a mismatch between the source (2.55) and binary (2.56) versions of the rGADEM package on the bioc release page.

Is this expected? Who can I notify to fix if not?

https://bioconductor.org/packages/release/bioc/html/rGADEM.html

There is a mismatch because the source version of the package is failing. See the build report: https://bioconductor.org/checkResults/release/bioc-LATEST/rGADEM/ . The versions will match when the ERROR is resolved.