The theme resets itself

Hi

I am currently working on two web sites and use free version of Vantage theme. (https://siteorigin.com/theme/vantage/). I customized the menu of the theme (changed color of the background and the letters in editor) and everything seems to be good, but two days ago the themes were reset to the original color. So I changed the colors (in wp – Editor ) and one of the themes is still with customized menu, but the other one turns back to original color few hours after the customization. Any idea what is the problem?

Here are the links of the sites:
https://goinvest.com.mk/ (still customized menu)

https://velaning.com.mk/ (the menu that resets itself few hours after changing the codes in editor)