When testing, this seems to happen when the instant blocks are in any order.
It might be related to the fact that any container with 2 or more instant blocks (including comments, even though they are ignored in code, and thus shouldn’t be causing the timing of the code to change) will cause the rule to run at 30 times/sec instead of the usual 60 times/sec.
But it also happens when the first rule is set to When Game Starts, so it’s not just a coincidence.
THT might not be able to fix this fully (because in order to do that, they’d have to find a way to make rules with containers with >1 instant block run at 60 times/sec like it did in player 1.5.x, which is very risky), but they’ll at least be able to fix it in the case a user uses When Game Starts for the first rule.
Technically, nothing has really changed between players 2.2.3 and 3.0.0 (other than the unstable nature of player 3.0.0 likely due to the newer PIXI version. I seriously think that version is too unstable for Hopscotch…)