Battery Incompatible message when using VG-C2EM

[MBPHOTOG]

I purchased 2 of these units new in Dec. 2016. Almost immediately I began experiencing this message on the monitor: "Incompatible Battery Use Correct Model". I'm using SONY OEM NP-FW50 batteries. These 2 units were exchanged for 2 new units in Dec. 2018 & the replacements exhibited the same issue. This is very inconvenient especially when working in the field. One of my colleagues has also had this issue. Last month I sent one of the units in to Sony Pro for repair & they replied that the problem could not be rectified. In desperation I purchased a third unit last month & so far it's working fine. Has anyone else in this forum experienced this problem & had a satisfactory resolution?