It'd be worth posting a forge log, methinks.
Also worth noting that I tried the test myself (under both 1.73 and 1.74pr20), and could not reproduce Lupus's results. My turtle successfully runs - and keeps running - its startup script, regardless as to whether I just close and re-open the world, or close and re-open the whole game (the latter scenario being the one where it breaks for him). Doesn't seem to matter if I pick the (chunk-loaded) spawn area or move away from it, fly away from the turtle then return, whatever... turtle goes spin-spinny-spin-spin.
That said, I've seen this bug reported over and over since joining this forum. Presumably it has multiple triggers. Beats me how many of those remain from back then.
1.5 -
1.63 -
1.65 -
1.73
The one specific time I can remember encountering this issue myself was on a 1.73 SMP setup, where I only needed to manually boot my systems back up and they resumed normal operation with further server reboots from that point on. My assumption is that an abnormal server shutdown triggered it, in that particular case - if CC decided that all computers in the world had crashed, then it'd save all their states as "off", and therefore wouldn't start them when they next chunk-loaded. I may've seen it on other occasions, but if so they were few and far between (months apart at least), never often enough to pay attention to, let alone a "constant thing".
But even if you put aside that most users who encounter bugs don't report them, this one seems prevalent to the point where there have been many cases where users have been under the impression that this is
expected behaviour, and were surprised when informed that no, they should not in fact have to manually click their computers every time they want to turn them on.
So I've no idea as to how common it really is. It's common enough that there's
at least one script specifically written to help work around it, anyway.