I’m sorry you had a crash and you lost 2,5 hours of work. Always super irritating and sad.
This is an alpha version and therefore chances are it will have bugs like this. So you are right, you need to remember to save more often. With the next release (Alpha 8) we do have an autosave feature, so that will come in handy. 😉
I am grateful that you took the time to test and reproduce the bug again the day after. Also you precise explanation is great. This makes it sooo much easier for us to find the problem and correct it. Thank you so much!