Where from is start.sh called?
It is not /etc/rc.local?? => I commented it out and no change.
?
Where from reads SBITX the APP the time?
It starts every time with the UNIX-Time starting point in 1970....
ZBITX gets it from network or from the RTC.
WSJT-X from there, because it shows the correct time.
?
Before the upgrade the time on zBitx was correct and the sbitx app got after a short delay the correct time too.