Describe the bug
When an array is passed as the format argument to dayjs.utc(), UTC mode is not used: the date is parsed in the local timezone.
dayjs() accepts an array for the format parameter (with the customParseFormat plugin), so it’s easy to assume dayjs.utc() does too. With an array, dayjs.utc() does not throw; it silently parses in local time, which can cause subtle bugs (e.g. tests passing only when TZ=UTC).

To reproduce

const dayjs = require('dayjs');
const utc = require('dayjs/plugin/utc');
const customParseFormat = require('dayjs/plugin/customParseFormat');

dayjs.extend(utc);
dayjs.extend(customParseFormat);

// With a single format, result is UTC midnight (correct)
const single = dayjs.utc('1995-05-01', 'YYYY-MM-DD');
console.log(single.toISOString()); // '1995-05-01T00:00:00.000Z'

// With a format array, result is local midnight (incorrect)
const withArray = dayjs.utc('1995-05-01', ['YYYY-MM-DD', 'YYYY-M-D']);
console.log(withArray.toISOString()); // e.g. '1995-05-01T23:00:00.000Z' in UTC+1

Stackblitz link https://stackblitz.com/edit/dayjs-playground-8cua8kja?file=index.js

Expected behavior
Either:

• Support format arrays and parse in UTC (same semantics as single-format dayjs.utc(date, format)), or
• Reject array format (e.g. throw error)

Likely cause
In customParseFormat, when format is an array, the code uses d.apply(this, args) (the default constructor) instead of the UTC constructor, so each format is tried in local time.

Information

• Day.js Version 1.11.13
• OS: macos
• Browser: NA
• Time zone: NA