Problem with pushback

[Dcamp70]

With version 3.7.4, pushback has problems. When selecting the start button, pushback doesn't start immediately; you have to press it twice more to start operations. At the end of operations, when the tractor lowers the plane's nose, you hear the same sound as the landing gear touching the runway during landing.
Pmdg737-800
FS2020

[virtuali]

When selecting the start button, pushback doesn't start immediately; you have to press it twice more to start operations

Which start button ?

At the end of operations, when the tractor lowers the plane's nose, you hear the same sound as the landing gear touching the runway during landing.

That's normal and always happened when releasing the airplane after lowering the nose, you can of course disable the raising function in the airplane profile, if you don't want it.

[Dcamp70]

In gsx menu when I select the start pushback voice

[virtuali]

In gsx menu when I select the start pushback voice

You mean you call the normal Departure ?

[Dcamp70]

Yes

[virtuali]

Just tried it now, no issues, called Departure, the pushback appeared and it worked immediately. Please be aware of the constraints on the PMDG: in order to continue with departure, you must first Dismiss the PMDG GPU.