[Nut-upsuser] why did self test warn?

[James]

The battery was replaced in December and the output from upsc was:
$ upsc desktop_ups
battery.charge: 100
battery.charge.low: 10
battery.charge.warning: 20
battery.mfr.date: CPS
battery.runtime: 1020
battery.runtime.low: 300
battery.type: PbAcid
battery.voltage: 13.5
battery.voltage.nominal: 12
device.mfr: CPS
device.model: UPS CP850AVRLCD
device.type: ups
driver.name: usbhid-ups
driver.parameter.pollfreq: 30
driver.parameter.pollinterval: 2
driver.parameter.port: auto
driver.parameter.synchronous: no
driver.version: 2.7.4
driver.version.data: CyberPower HID 0.4
driver.version.internal: 0.41
input.transfer.high: 140
input.transfer.low: 90
input.voltage: 122.0
input.voltage.nominal: 120
output.voltage: 122.0
ups.beeper.status: enabled
ups.delay.shutdown: 20
ups.delay.start: 30
ups.load: 32
ups.mfr: CPS
ups.model: UPS CP850AVRLCD
ups.productid: 0501
ups.realpower.nominal: 510
ups.status: OL
ups.test.result: Done and passed
ups.timer.shutdown: -60
ups.timer.start: 0
ups.vendorid: 0764

The output now is:
battery.charge: 100
battery.charge.low: 10
battery.charge.warning: 20
battery.mfr.date: CPS
battery.runtime: 870
battery.runtime.low: 300
battery.type: PbAcid
battery.voltage: 13.5
battery.voltage.nominal: 12
device.mfr: CPS
device.model: UPS CP850AVRLCD
device.type: ups
driver.name: usbhid-ups
driver.parameter.pollfreq: 30
driver.parameter.pollinterval: 2
driver.parameter.port: auto
driver.parameter.synchronous: no
driver.version: 2.7.4
driver.version.data: CyberPower HID 0.4
driver.version.internal: 0.41
input.transfer.high: 140
input.transfer.low: 90
input.voltage: 119.0
input.voltage.nominal: 120
output.voltage: 119.0
ups.beeper.status: enabled
ups.delay.shutdown: 20
ups.delay.start: 30
ups.load: 28
ups.mfr: CPS
ups.model: UPS CP850AVRLCD
ups.productid: 0501
ups.realpower.nominal: 510
ups.status: OL
ups.test.result: Done and warning
ups.timer.shutdown: -60
ups.timer.start: 0
ups.vendorid: 0764

These changed:
battery.runtime:
ups.load:

Is the battery dead again?
Do I need a new UPS?