Battery orientation at replacement

[TomHayes]

I have a number of BackUPS XS1500 at my church. The other day one unit started beeping with the battery icon on the display flashing. I purchased a new battery and upon opening the unit I saw that the old battery was oriented red side up. It was inserted in the right direction with the connections facing in. At the time of replacement the display said there was 35 min of backup time available. (35 min seems OK so why is the battery icon flashing and the alarm going off?) It's running at 18% load. Since the manual says green side up, I inserted the new battery that way. I let it charge overnight and the display still says 35 min runtime, the battery icon is still blinking but the bargraph says 100% battery charge.  I'm puzzled by the fact that two different orientations of the battery display the same 35 min runtime. I was waiting for sparks when I inserted the battery per the manual rather than the orientation of the old battery. Is there a safety circuit in the battery to keep it safe when inserted upside down? Is there something wrong with UPS?

Regards,

Tom Hayes