When Strato saw my solution he reported it, saying climbers shouldn't shimmy off stacks. Soon afterwards, Namida fixed it so shimmiers could not shimmy off stacks.
The purpose of allowing Climbers to always be assigned Shimmiers is to make it easier to transition from Climber>Shimmier when playing in real-time (particularly in Classic Mode, where skill queuing is deactivated). It's an intentional design decision and won't be reverted.
I think Strato wouldn't like this Superlemmix 2.1.1 change either since now this level can be backrouted again.
Unless it's a bug (which it isn't, in this case), behaviour won't be changed in order to preserve existing content that's already available for, and playable in, NeoLemmix.
This goes for my own content as well - please don't take it personally.
The answer here is to fix the level so that it's playable in SuperLemmix, or replace it with a different level. With that said, it's also worth mentioning that whilst SLX development is in a fairly fluid, transitionary period,
it's possible that more physics changes will be made until we're settled on a more or less stable version, which I'll be sure to announce as and when that time comes.
I'm going to try to put together some sort of design schedule so that players know what's coming and what to expect in terms of possible changes, but bear in mind that I'm still responding to other people's ideas as well as implementing my own (as an example, it's been suggested by a number of people that the Fencer tunnel be made wider, and this is something I'll get around to looking at in due course).
As you've no doubt already seen, I absolutely will fix bugs that arise as long as they're not intentional behaviour. So,
please do continue to report anything you spot, but if it's related to a design decision that's been made for SuperLemmix, it's very unlikely to be actioned upon unless it's something that clearly breaks the game itself.