Why are some snaps missing from Discover searches

I am having a strange issue with Plasma's Discover

Not all snap packages are shown in a search.

If there is only a snap package and a regular Ubuntu (.deb) package it will show both packages.

However if there is a Ubuntu package, a Snap package and a Flathub package of the same program it will only show the Ubuntu and the flathub versions.

I have the Ubuntu repos set as default, but if I change the default to Snap packages it will then show the Ubuntu package and the snap package but the flathub version will now be completely missing.

Am I missing some setting with Discover here, does flatpak automatically override Snaps with not remedy or have I run into a bug with snaps discover or flatpaks? (if it matters I am using 19.04 version of plasma, not the ppa, is this something that was fixed in the newer versions of plasma?)

I have added some screenshots below to help clarify my question

System Info:

This is with snaps as default, flathub version is missing:

This is with Ubuntu sources as default, notice the Snap package is now missing and only the flathub is showing as a second option:

This is a search for chromium with ubuntu repos as default. There is no version of the Chromium browser in flathub so it shows the snap version as well as the ubuntu version. There is no snap version of B.S.U. so it shows the flathub and ubuntu versions of B.S.U like expected: