Workflow - block corruption -> empty blocks

We've hit a major bug in workflows a second time now. So we're reporting it.

problem: workflow blocks became completly empty. Also new blocks throw a server error imidiently.
This only affects blocks in the main workflow, but not also blocks in multistep functions.
We've resolved it by reverting to previous published version, there was some loss of progress, but lucky nothing major.

It is a bit scary to think, that work can be lost just like that.