Thank you for your help @Anshu kumar!
Yes, I installed it from the Google Play Store. I even uninstalled and then reinstalled to make sure.
I'm using a Samsung Galaxy A5 (2017)
I already tried the stable version, then I installed the Beta to see if it makes things work. It doesn't make a difference on my device.
Edit: I noticed some other weird behaviour. In apps, the correct URL is detected but Enpass doesn't show the matching entry, even though it exists.