She did the bangs before and didn't keep them long. Someone on FJ said Joy said in her comments (I couldn't find it, but there are a million comments) that she didn't dye her hair; it's just wet from the rain. Which seems kind of unbelievable, but if you look at her pictures from the last time she had bangs, her hair looked super dark then, too, but then looked lighter again shortly thereafter. So either Joy uses dye that washes out within days, or her hair just drastically changes color depending on lighting, filters, etc.
Example of last time she had bangs and her hair was super dark: https://www.instagram.com/p/B41JmGeJuXb/ (Nov 13, 2019)
Three days later, still has the bangs, hair shade looks so much lighter: https://www.instagram.com/p/B48yPU0pveU/