Different fonts when running flatpak

hi there… I noticed a difference in my app when running on Flatpak compared when running native or on Snap…

this is how it looks on flatpak:

this is how it looks on native and snap

as you can see the fonts are much bigger on flatpak

Any idea on how to fix it?

This is my manifest:

flathub/org.dpsoftware.FireflyLuciferin/blob/master/org.dpsoftware.FireflyLuciferin.json

{
  "id": "org.dpsoftware.FireflyLuciferin",
  "runtime": "org.freedesktop.Platform",
  "runtime-version": "24.08",
  "sdk": "org.freedesktop.Sdk",
  "command": "FireflyLuciferin",
  "finish-args": [
    "--share=network",
    "--share=ipc",
    "--socket=pulseaudio",
    "--socket=x11",
    "--device=all",
    "--filesystem=xdg-documents",
    "--filesystem=xdg-download",
    "--talk-name=org.kde.StatusNotifierWatcher"
  ],
  "modules": [
    "shared-modules/libayatana-appindicator/libayatana-appindicator-gtk3.json",
    {
      "name": "cuda-toolkit",

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