Hi, my Linux Mint Debian Edition workstation is connected to a MGE Protection Center 675. Under LMDE Update Pack 3 everything worked fine. After LMDE Update Pack 4, the following recursion occurred: The panel icon shows a dashed red circle on a black empty field (the default icon when a program does not provide an icon). Hoovering over the icon gives the message "Adaptor is online Your UPS is empty" Which is obviously not the case. Only once have I momentarily seen the normal UPS icon, together with a message that my UPS was fully charged.
I guess there were some icons missing in your icon theme, git master certainly carries the respective icon for ups. So not a bug in xfpm.