I also just did a clean install on my SD card with recalboxOS-4.0.0-beta5 on my RPI3. I enabled WIFI and was able to connect. I went into KODI and it showed Jan 01 1970. I changed the timezone to my timezone and rebooted. Still no date change. Again the only thing it affects is exodus in Kodi, I can only watch movies from the 70's, and I can confirm this is true, cause I have installed KODI and Exodus on my laptop and it works well with the correct date.
I will try and install an earlier version of recalbox and see if that works or not.