I am experiencing the same issue.
I upgraded from ISY994 to EISY a few months ago. Before upgrading, the 3 Insteon Motion Sensor II 2844s I am using were reporting Battery Powered correctly along with a usable relative (but not accurate) Battery Level. After upgrading, Battery Powered usually reports "False", and Battery Level is rarely updated.
It seems like the much faster EISY isn't waiting long enough for the MS II to complete its transmission of the data.
Any advice is welcomed.