There is a problem in the current SobiPro version (1.3.1) which clears the entry publication dates (valid from, valid until and creation dates) after editing such an entry from the front-end.
As a temporary fix for this problem, please edit /components/com_sobipro/etc/config.ini (or create override for configuration file) and modify there lines:
[date]
;publishing_format = "Y-m-d H:i:s"
publishing_format = "j F Y H:i:s"
To
[date]
publishing_format = "Y-m-d H:i:s"
;publishing_format = "j F Y H:i:s"
This problem is ONLY related to SobiPro 1.3.1! It is fixed in 1.3.2.
Regards
Sikor