Murenacloud and keepass

I’m using keepass, and my database is stored on my murenacloud.
On my phone I have the NextCloud app, so that my cloud shows as a drive, along with my local drives. In the KeePass app (KeePassDX or Keepass2Android), I’ve open the database by selecting it on the NextCloud drive. It’s been working fine like that for 1 or 2 years, and suddenly, about 10 days ago, it stopped working. When I tried to open KeePass, I got a message saying “cannot download file”.
If I copy the file on a local drive drive it works fine again. So neither my file nor the app are corrupted.
I finally found that with Keepass2Android, I can open the database not as a local file file picked on the NextCloud drive, but directly with the NextCloud credentials. And by doing it this way, it works.
Any idea why the previous method stopped working? Have there been updates by Murena that might cause a restriction for downloading a KeePass file, though I can see it on the drive and open other kinds of files ?

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