Why is my printer using both black cartridges when that is not the way it usually works

[gabagoo]

This printer is a JV150-130 and up until I noticed this always uses one cartridge at a time, when it is empty it moves to the secondary cartridge. In the pic you can see it is pulling black from both which could mean something has gone wrong. Has anyone seen their printer do this?

 

[netsol]

firmware update, changing preferences?

 

[APCInk]

Normally the printer will favor the cartridge with the lowest remaining ink first, however as cartridges get near expiration date the machine will favor oldest ink first to use it up before it expires. Check your expiration dates - this may be why it switched.

 

[Solventinkjet]

As APCink said, most likely one of the cartridges is expiring sooner than the other and it switched to use the closer expiration date first.

 

[gabagoo]

Yes that must be it as when I loaded the new cartridge in the beginning it showed I had 2 months. Thanks guys...smart machine