Worked at a startup that built a 3D modelling tool in the browser. They did a major refactoring that was still ongoing. At this point in the core team of 5 they churned through 10 engineers in 1 year. So when I started my job I learned that you could neither create a working build nor would any of the tests run. (Not to speak about the CI pipeline) Eventually the build could be fixed as well as the few tests. But as it turned out every basic user functionality had to be rewritten and the structural refactoring was still in progress.

IMHO the refactoring sounded very reasonable since the old code base was unmanageable. But there was a culture of extreme pressure from the CTO, making everyone haste through tasks preventing everyone to do "proper engineering". At the time the CTO was in some sort of permanent absence already. Afterwards the team lead left because of burnout, I also left and later on I heard they closed down the company.

Actually I've seen similar destructive refactorings at other places. At one they also had a lot of subtle problems leading to many user complaints. It could be fixed but by then it was already too late.

IMHO refactorings are great but it's always necessary to keep regressions in check all the time and really understand the design decisions of existing code.