It seems to me, that the English ordinal suffixes in date formats in {{#time:}} are not supported: {{#time:jS F Y|January 20, 2000}} gives 20S January 2000 rather than 20th January 2000.
Topic on Help talk:Extension:ParserFunctions/2020-2024
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I don't see a support for them as well. It's probably worth making a feature request as other languages may also benefit from this. A workaround can be a template like:
{{{1}}}{{#switch: {{#expr: {{{1}}} mod 100 }}
| 11 | 12 | 13 = th
| #default = {{#switch: {{#expr: {{{1}}} mod 10 }}
| 1 = st | 2 = nd | 3 = rd
| #default = th
}}
}}