Multiple calls to utcOffset cause formatted time to drift when time is across Daylight Savings Time boundary

[zzzzBov]

Describe the bug
Assigning the same utcOffset multiple times causes the formatted time to shift when the time is across a Daylight Savings Time boundary.

The following code demonstrates the issue:

const dayjs = require("dayjs");
const utc = require("dayjs/plugin/utc");

dayjs.extend(utc);

console.table({
  // March 13th 2021 at 12:00PM -04:00 is during Standard Time

  // Force a specific timezone offset.
  "13th 1xUTC offset": dayjs("2021-03-13T16:00:00.000Z")
    .utcOffset(-4)
    .format("h:mm A"),
  // Force a specific timezone offset multiple times. This should have no
  // effect, but unfortunately the formatted time shifts.
  "13th 2xUTC offset": dayjs("2021-03-13T16:00:00.000Z")
    .utcOffset(-4)
    .utcOffset(-4)
    .format("h:mm A"),
  // Force a specific timezone offset multiple times but reset in-between.
  // This has no effect and appears to be an adequte work-around.
  "13th Change UTC offset": dayjs("2021-03-13T16:00:00.000Z")
    .utcOffset(-4)
    .utcOffset(0)
    .utcOffset(-4)
    .format("h:mm A"),

  // March 14th, 2021 at 12:00PM -04:00 is during Daylight Savings Time

  // Force a specific timezone offset.
  "14th 1xUTC offset": dayjs("2021-03-14T16:00:00.000Z")
    .utcOffset(-4)
    .format("h:mm A"),
  // Force a specific timezone offset multiple times. This should have no
  // effect, but it's likely that the time would shift if tests are run during
  // standard time.
  "14th 2xUTC offset": dayjs("2021-03-14T16:00:00.000Z")
    .utcOffset(-4)
    .utcOffset(-4)
    .format("h:mm A"),
  // Force a specific timezone offset multiple times but reset in-between.
  // This has no effect and appears to be an adequte work-around.
  "14th Change UTC offset": dayjs("2021-03-14T16:00:00.000Z")
    .utcOffset(-4)
    .utcOffset(0)
    .utcOffset(-4)
    .format("h:mm A"),
});

Expected behavior
The output table ought to return "12:00 PM" for all cases.

Actual behavior
The "13th 2xUTC offset" value produces "11:00 AM" during DST.

Information

• Day.js Version v1.10.5
• OS: Windows
• Browser: Chrome, Node
• Time zone: All