As said above, it's a (very annoying!!) bug. I struggled with it for a good while.
I don't know that Hemmola's fix works......I don't think it does.
The workaround I know of is a bit annoying, fiddly and restrictive. It goes like this (video posted at end to illustrate):
---make a fixed first cam at start, then make 2nd one identical but triggered before the start line.....then go back to first cam and continue as normal inserting cams before the last one. This seems to 'close the loop' and ensures Hemmola's "Camera 21" is always set right, from the get-go?
Video showing workaround - thanks to Andre/ATR cams
**ETA - Hemmola's workaround sounds better (if it works). Could you better explain it, Hemmola? SFAIK that doesn't work, the error just replicates on Camera 21 in your example, and doesn't alter Cam20 which also remains broken.
Could you better illustrate your workaround, please? Because it sounds a much better 'fix' than the one I have been shown.