Seems that after upgrading to DNN 9.2.0 and old issue re-appeared when using GTM configuration script as described in: http://www.dnnsoftware.com/community-blog/cid/155268/using-google-tag-manager-with-dnn
It was caused back then by injecting the GTM code in the wrong event in the page life cycle if I remember correctly:
On my DNN 9.2.0 site I can no longer save module settings:
from browser console:
from dnn admin log:
Removing gtm configuration "fixes" the issue...
tx in advance,