I'll check a few things when I am at the big rig.
I don't know what happens if you haven't "signed up" and "signed in", so do make an account for yourself. I prefer anonymity / no signing up ever but caved in this case as I have for a handful of important things.
Just now the (my) wokwi was odd, but I'm on an iPad at the moment and I've already found it to be at least inconvenient, but it should make anything weird happen.
So if you are on a tablet, try it on a real computer.
Lastly, you may be running into one of the problems I am worrying you about - the KA pulse coming at a bad time with respect to the end of the video period.
More later. The wokwi has quite a bit of documentation as far as steering around the basic functions you expect, like save, rename &c., I think they concentrating on the actual thing, but most of the time when I've asked for help they point me into the docs, and I find that I had been less than thorough in my searching.
a7