BUG #17556: ts_headline does not correctly find matches when separated by 4,999 words

The following bug has been logged on the website:

Bug reference: 17556
Logged by: Alex Malek
Email address: magicagent(at)gmail(dot)com
PostgreSQL version: 14.4
Operating system: Red Hat
Description:

Correct results when 4,998 words separate search terms:

# select ts_headline('baz baz baz ipsum ' || repeat(' foo ',4998) || '
labor',
$$'ipsum' & 'labor'$$::tsquery, 'StartSel=>, StopSel=<,
MaxFragments=100, MaxWords=7, MinWords=3') ;
ts_headline
---------------------
>ipsum< ... >labor<
(1 row)

Add one more word between terms being searched for, to total 4,999, and
terms are not found:

# select ts_headline('baz baz baz ipsum ' || repeat(' foo ',4999) || '
labor',
$$'ipsum' & 'labor'$$::tsquery, 'StartSel=>, StopSel=<,
MaxFragments=100, MaxWords=7, MinWords=3') ;
ts_headline
-------------
baz baz baz
(1 row)

Works correctly if "&" (AND) is replaced by "|" (OR)

# select ts_headline('baz baz baz ipsum ' || repeat(' foo ',4999) || '
labor',
$$'ipsum' | 'labor'$$::tsquery, 'StartSel=>, StopSel=<,
MaxFragments=100, MaxWords=7, MinWords=3') ;
ts_headline
---------------------
>ipsum< ... >labor<
(1 row)

The "MinWords" argument and the number of words before the first term being
searched for alters the results:
Removing one word before the first search term and ts_headline will match
first term:

# select ts_headline('baz baz ipsum ' || repeat(' foo ',4999) || ' labor',
$$'ipsum' & 'labor'$$::tsquery, 'StartSel=>, StopSel=<,
MaxFragments=100, MaxWords=7, MinWords=3') ;
ts_headline
-----------------
baz baz >ipsum<
(1 row)

Now reducing MinWords from 3 to 2 and terms are once again not found:

# select ts_headline('baz baz ipsum ' || repeat(' foo ',4999) || ' labor',
$$'ipsum' & 'labor'$$::tsquery, 'StartSel=>, StopSel=<,
MaxFragments=100, MaxWords=7, MinWords=2') ;
ts_headline
-------------
baz baz
(1 row)