PostgreSQL CREATE TEXT SEARCH DICTIONARY reports stop-word on thesaurus file row that actually do not contain the reported stop-word

Question

I try to create thesaurus from the thesaurus file moby.ths using the query

CREATE TEXT SEARCH DICTIONARY thesaurus_moby (
    TEMPLATE = thesaurus,
    DictFile = moby,
    Dictionary = english_stem
);

Postgres reports the following error:

[F0000] ERROR: thesaurus sample word "over" is a stop word (rule 63944)

When I open moby.ths then the line 63944 does not include "over".

1. Is the rule number not the same as the line number in .ths file?
2. How can I find the row in .ths file that corresponds to rule number?

UPDATE:

1. There are no "over" in .ths file sample side.
2. Does Postgres do some preprocessing by dropping rows from original .ths file and creates its rule set?
3. If so, how can I see the rule set that Postgres is working on and where the rule 63944 is probably present?