Now add on the fact that different teams had varying levels of frontend competence. This led to some webapps being in (badly written) React, some in Angular, some in JQuery and one in Angular2 as well. Some were java API backed, some were NodeJS backed and one used Ruby in the backend. Oh yeah, and each had different datastores as well.
Now alongside this, there's no central auth framework, so each webapp had their own way of how to determine user auth (there was a shared cookie thankfully on the *.company.com domain), so there were 6-7 possible login and logout pages as well.
When the company had a brand redesign and needed all customer facing stuff to re-align with new design, we had to literally re-design 6 dashboards which have used different paradigms and different tech stacks.
To this date, the dashboard still exists and is used by customers (Main dashboard for a company valued at $500M+) and the most common issues are issues related to Auth (eg. random logouts when switching tabs), data inconsistency (They have crons which update data from one DB to another, but it's not immediate) and an inconsistent design and UI behaviour (since JS is also different for each app) which pisses off many users.
Till date, I'm not sure who signed off on this pointless dashboard design.