I just found the issue: I forgot to use Delta-time specifically in the elasticity calculation. As a result, a higher FPS makes the chain less elastic. Haha🤦. Your CPU is about 2x faster than mine, so perhaps if you open several apps and games in the background, you'll be able to grab the chain extender! Haha
I'm uploading a fixed version as soon as the voting ends. Sorry for this, and thanks for helping me troubleshoot