Theme Logo sometime fuzzy - sometimes not ..?

Hello all,

I set up the logo in the customizer of BB Theme, see picture below.

The Logos uploaded are:

  • Regular Logo: 120px
  • Retina Logo: 726px

The Problem:

  • on some pages the logo shows up crisp clear
    e.g. https://clevermom.de/

  • on some pages the logo shows up fuzzy …?
    e.g. Blog
    e.g. MOBILE Version!

There is no difference using another laptop or using another browser (tested with FF and Chrome)

I have no idea why …?

Can you help me out?!

customizer|244x500 !
Logo fuzzy|690x127 !
logo not crisp clear|690x133