Arnost

Yes, referencing CSSPlugin fixed it, but moving to the new syntax will be better. Old habits die hard I guess ? Thanks for mentioning that, I would have not guessed the new syntax would make a difference!

Hi @GreenSock and @OSUblake, I'd like to reinvestigate this issue. I have started bumping into this issue working with Nuxt in production mode. Development runs fine, but in production the CSSPlugin seems to get tree-shaken. I've produced a minimal repro case here: https://github.com/ParallelUniv3rse/gsapBugRepro I'll be happy to help any way I can

Hi Zach, I've stumbled upon the same issue here and I'm not using className tweens. The issue appears when using the four-value syntax for background tweens. See minimal reproduction case: https://codepen.io/paralleluniv3rse/pen/wvvEGZv