A while back, I was made aware of an issue where the Notes client will increase the size of fonts in emails when sent back and forth multiple times. This link points to the problem description:
https://www-304.ibm.com/support/docview.wss?uid=swg21201323
The work around is to add a few variables to your servers notes.ini to address this. So what does this have to do with Quickr?
I was recently discussing a Quickr 8.x > 8.5.1 upgrade when this was encountered. If you have implemented the work around as listed in the above technote, it will break the Quickr login page. The rendered HTML will be malformed, and you will not be able to use the Quickr login page which allows for non-directory members logging into the server / places.
Took a bit of figuring and a PMR, and I suspect this is a rare combination of circumstances, but if this can help anyone else, here it is.