apt-get install fails when UNRELATED package list is invalid

[seahen]

1) Description: Ubuntu 19.04
Release: 19.04
2) unknown (see below)
3) Even when a package list from one source is invalid, I can still apt-get install and apt-get update packages from other sources, as long as they don't depend on packages in the bad list.
4) I can't install a package from *any* source, even the ones that still yield valid package lists.

On Xubuntu 19.04, I have the following in my sources.list:

deb https://adoptopenjdk.jfrog.io/adoptopenjdk/deb/ disco main
deb-src https://adoptopenjdk.jfrog.io/adoptopenjdk/deb/ disco main

Currently those sources yield invalid package lists. However, installation of a package fails even when it comes from *another* source.

$ sudo apt-get install stress
Reading package lists... Error!
E: Encountered a section with no Package: header
E: Problem with MergeList /var/lib/apt/lists/adoptopenjdk.jfrog.io_adoptopenjdk_deb_dists_disco_main_binary-amd64_Packages
E: The package lists or status file could not be parsed or opened.

Shouldn't this affect only packages that come from the faulty package list or depend on ones that do? I get the same error when running

$ apt-cache policy apt-get

so I can't determine what version of apt-get I'm encountering this bug in.

[seahen (seahen123)]

#1848974 may be a duplicate of this bug.

[seahen (seahen123)]

$ apt-cache policy apt
E: Encountered a section with no Package: header
E: Problem with MergeList /var/lib/apt/lists/adoptopenjdk.jfrog.io_adoptopenjdk_deb_dists_disco_main_binary-amd64_Packages
E: The package lists or status file could not be parsed or opened.

[seahen (seahen123)]

I have the same issue if I try apt instead of apt-get.