Comment 3 for bug 1795557

i think i hit the same issue:

[root@XXXX:~] # apt list --upgradable -a
Listing... Done
shim-signed/bionic-updates 1.37~18.04.2+15+1533136590.3beb971-0ubuntu1 amd64 [upgradable from: 1.34.9.2+13-0ubuntu2]
shim-signed/now 1.34.9.2+13-0ubuntu2 amd64 [installed,upgradable to: 1.37~18.04.2+15+1533136590.3beb971-0ubuntu1]
shim-signed/bionic 1.34.9+13-0ubuntu2 amd64

[root@XXX:~] # apt dist-upgrade shim-signed
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Error!
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 shim-signed : Depends: shim (= 15+1533136590.3beb971-0ubuntu1) but 13-0ubuntu2 is to be installed
E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.