Sample inhomogeneities such as interface roughness, impurities, or crystal lattice dislocations can be the cause for two-magnon scattering in ferromagnetic thin films. Using an element specific time-resolved technique, we show experimentally that in CoMnGe/Au/NiFe trilayers the uniform magnetization precession in NiFe (Py) layer can be influenced by magnetic stray fields emerging from the domain walls of micrometer size magnetic ripple domains in the CoMnGe layer. We have found that these stray fields cause a phase shift of the transversal dynamic magnetization component of the precessional motion in the Py layer. We attribute the observed phase slip in precession to the two-magnon scattering process.