The most useful procedure for reporting bugs is:
1) Create an account on https://bugzilla.wikimedia.org/ 2) Follow the "Enter a bug report" link 3) Pick "Wikimedia" as a product, and "General" as the component unless a more specific component is applicable 4) Enter a description and file the bug 5) Add bug 41184 in the "Blocks" section (this will only appear once the bug is created). This will add it to the tracking bug and notify various folks who are working on the migration.
Reporting in the lounges/pubs is less useful because it's harder to monitor, but if you see folks posting issues there, please help guide them towards Bugzilla.
I recommend importing this template: https://en.wikipedia.org/wiki/Template:Tracked
which is handy to link on-wiki discussions to relevant bugs.