The Genshin Impact team have provided an explanation of sorts on some of the fixes introduced in 1.4
One of the fixes revolved around a character sitting down could be lifted by the crystal platfom from Solar Isotoma. Additionally, there was an issue fixed in co-op where several characters would sit in the same spot. These two issues saw fixes with the team offering an explanation.
Apparently, in co-op mode, while these seemingly innocuous scenarios could be pretty funny, they could also inadvertently disrupt the experience of the other player. To smooth this out, the team provided fixes for these with 1.4.
A few other issues were discussed, but a big one was one where damage from major reactions like Shatter, Electro-Charged, Superconduct, Overloaded, and Swirl from character actions would scale depending on Elemental Mastery and the Elemental Reaction bonus.
The team explained, that in 1.4,
“If Ganyu receives an Elemental Mastery bonus due to the actions of two characters, the Elemental Burst-triggered Superconduct reaction will receive a damage bonus based on Ganyu's twice-increased Elemental Mastery as long as it is during the duration of the bonus effects (no matter if the bonus is received before or after the Elemental Burst is unleashed).”
This bonus is then bound by the duration of the talent effects. However, this has some knock-on changes as they explained. This increases the coverage of the temporary Elemental Mastery bonus. It also means that you can no longer stack the Elemental Mastery bonus for a few skills.
You can check out the entire post here.