Is System-Repeat every tick? How would I know that by reading the manual?
Simply repeat the event a given number of times. This tests any conditions following it on every repeat, and if those conditions are met also runs the actions and any sub-events on every repeat."
It seems to be because it needs a condition to break the infinite loop, which is confirmed by debugger. The manual states it tests "any conditions", not that you have to have conditions to break the infinite loop. This caused me some time in testing initially because I couldn't figure out why it wasn't working and I didn't fully figure it out until I found other people's code examples and then a lot of testing.
Unless this is some general rule which was stated at the beginning of the manual that "everything is per system tick" unless stated otherwise.
From logic alone, one would think if you have repeat something x times, it should be repeated x times and that's it.