Some websites still open in app, even when that app is set to NOT open supported links
In Firefox settings, I DO have "Open links in apps" enabled, because I do want most sites to do this. However, there are some specific sites that I DON'T want to open in app. For most of these (e.g. Aurora Store), it is sufficient to open the App Info (in Android system Settings) and disable "Open supported links" (and also tap the "clear default preferences" button, if it's there). For those apps where I've disabled supported links, webpages will load normally in the browser, and there won't even be an "Open in app" option from the 3-dot dropdown menu for the website.
The problem is, some apps that have supported links disabled will still be opened when a link to their website is tapped in browser. One example of this is Tumblr. Tapping a link to any tumblr.com site will launch the Tumblr app instead (which is a particular problem because the Tumblr app currently has a bug where it cannot open links to specific pages, so it navigates to the homepage instead, which is useless. For this reason, it's imperative that Tumblr links open only in browser, at least until Tumblr fixes their bugs.)
Is there anything that I'm missing that will definitely prevent FF from launching an app, when that app is set to NOT open supported links? Is this a FF mobile bug that I should file on Bugzilla? Are there any workarounds (perhaps like a 3rd-party app that intercepts the intent to open Tumblr and redirects it back to the browser)?