zonedDateTimeFns.getOffset() only handles some values correctly

[kolton-musgrove]

      it('ignore defers to disambiguation option', () => {
        const offset = 'ignore'
        assert.equal(
          zonedDateTimeFns.getOffset(
            zonedDateTimeFns.with(doubleTime, { hour: -2, minute: -30 }, { offset, disambiguation: 'earlier' })
          ),
          '-02:30'
        )
        assert.equal(
          zonedDateTimeFns.getOffset(
            zonedDateTimeFns.with(doubleTime, { hour: -3, minute: -30 }, { offset, disambiguation: 'later' })
          ),
          '-03:30'
        )
      })

The previous two tests should correctly create an offset of 2.5 hours and 3.5 hours, respectively, but the second assertion returns a value of 2.5-hour offset.