Liberty 3 Pro Sounds worse in normal mode

I’ve been using my buds for about 5 months. Since this week I have a very strange problem.

While listening in ANC or Transparent mode everything sounds normal. But whem I switch to normal mode, sound becomes flat and bass is greatly reduced as if buds are in a very different EQ setting.

I tried resetting the buds but problem still persists.
Any thoughts about how to fix this issue?