Unit test fails under PHP 7.4.3

[cj-clx]

This unit test fails under PHP 7.4.3:

1) DateFormatTest::testWeeksin
Failed asserting that two strings are equal.
--- Expected
+++ Actual
@@ @@
-'in 2 weeks'
+'in 13 days'

[cxj]

Strangely, this test works correctly under PHP 7.4.7.