mtr --ps does not print fractional digits for FROM_UNIXTIME('1922.1')

The problem is repeatable with all server versions between 10.5 and 11.7.

I create this MTR test file:

SELECT FROM_UNIXTIME('1922.1');

If I run "mtr testname", it returns:

SELECT FROM_UNIXTIME('1922.1');

FROM_UNIXTIME('1922.1')

1970-01-01 04:32:02.100000

If I run "mtr --ps testname", it returns

SELECT FROM_UNIXTIME('1922.1');

FROM_UNIXTIME('1922.1')

1970-01-01 04:32:02

Notice there are no fractional digits.