i installed the last version of avidemux 2.6.21 64bit

i have noticed 2 issues

i don't know if it's the last version of avidemux or it's my mistake

1) i tried to add audio to a slideshow create with proshow procuder , and on many devises it doesn 't work and many players don't play audio , only vlc is able to do it
the container is mp4
here the info with media info , in this screenshot i haven't added audio

with avidemux i added my mp3 on audio select track
and with these settings

the result is

what's wrong? did i do a mistake ? is the last version buggy ? because with the older version i have never had any issues

2) out of sync after avidemux
extension mkv

avidemux settings

the avidemux output is Out of synch

best regards