V3 SE does not keep max speed and acceleration settings

got a problem with my Ender-3 V3 SE: it does not keep max speed and acceleration settings. It prints well PLA and TPU, but gets a problem with PETG. The latter requires probably fine tuning (which I do), but I can not set the upper limits for speed and acceleration. I follow the usual path - configuration → motion → Max speed and acceleration (updating numbers) → back (to motion) → store configuration. The problem is that during the printing process software seems to “adjust” back the speed and acceleration limits. This is happening when I use the filling = 100% (requiring long printing time); in this case software probably wants to speed up printing and increases sped and acceleration limits. As a result, printing quality is strongly reduced, Does someone experienced similar problem?