iCloud Drive text files being opened with Numbers
Before, everything worked fine with text files (.txt files) I have in iCloud Drive.
A tap on iCloud Drive, and another tap on a text file on my iPhone would open the file with Notes.
From some point on (I think I had the same text file opened at the same time on my Mac and my iPhone) iCloud Drive text files on my iPhone are being opened with Numbers.
From now on, when I tap an iCloud Drive text file on my iPhone I get Numbers opening that file.
When I tap the information icon next to the text file name, I get an info screen saying at the top right "Open in Numbers".
I the text file is a formatted file (.rtf) there is no problem; Notes opens that file; and the info screen, at the top right, for that file says nothing about the app that will open the file.
That happens only on my iPhone; I have a 5S, 64Gb, with the latest iOS 9.3.1
On my Mac everything is working fine.
I tried a "Reset All Settings" but that didn't work.
Any idea of what is going on and how to solve it?
iPhone 5s, iOS 9.3.1