I'm creating this bug report to link here a bug report I filed upstream and track progress.
the nextcloud desktop client is performing writes to the keyring file very few seconds. Every time it contacts the server to check for changes.
It looks like this is a regression introduced in version 2.6.1.
I have isolated the upstream commit introducing this and a single code line that can be commented out to stop this behaviour. The details are in the github issue here:
but simply commenting out that line is not a proper solution.
Created attachment 209166 [details]
I'm attaching a very simple patch I'm using as a workaround.
This patch makes the unwanted writes to the key ring stop.
It most probably has collateral effects on the remote wipe functionlaity.
Comment on attachment 209166 [details]
Upstream provided a fix for this. 
I created a code review on phabricator to import it.
A commit references this bug:
Date: Sun Dec 1 15:47:02 UTC 2019
New revision: 518779
Add patch to fix problem with keyring rewriting.
Submitted by: Guido Falsi