DDJ-SZ Audio Output Decrease Issue

I bought 4 months ago pioneer Sz Controlr

Before that I worked with The Sx controlr 

Almost every night I work I have a audio output level decrase

I did the latest update 1.18 firmwere and the problem is not resolved

in The Sx Controlr  it had not happened to me never

I go to Pioneer  Israel and canceled my mixer's limiter settings via (Cencel Load Prepere)

There is another solution? It's okay to work without a limiter device?

why its happend???