App Lounge - inconsistent behaviour when installing an outdated app version

/e/ version: v1.5.1-r & v1.5.1-RC-s
Device model(s): Beryllium
Device rooted: no

Summary

If App Lounge is set to manual updates, the user needs to manually update app. This can be done either in the "Update" submenu clicking on the blue "update" button for each app. OR the user can enter the app specific page to click on the blue "update" button.

In specific cases App Lounge shows an inconsistent behaviour: For instance when older versions of apps are installed straight from F-Droid. In this case App Lounge indicates those apps as updatable in the update submenu. But when the user enters the app specific page, there is no blue "update" button but a blue "open" button.

This behaviour seems to be reproducible with any app from within F-Droid.

The problem

Steps to reproduce

Open F-Droid and open the app specific page for "Monocles Browser"
Go down to the bottom of the app specific page > versions > select the oldest version of the app and install it.
Open App Lounge > "Updates" tab and then see the app specific page.

What is the current behavior?

Described above

What is the expected correct behavior?

When App Lounge identifies an app to be updated, this should be possible in the same way from the "Updates" submenu in App Lounge or form the app specific page for the respective app.

Technical information

none

Relevant screenshots