Q: error on updating collation version information

Dear all,

following an ICU upgrade, collations in a stock Debian PG 15.1
cluster now have divergent version information in pg_collations.

Now

gnumed_v22=> ALTER COLLATION pg_catalog."br_FR(at)euro" REFRESH VERSION;
ERROR: collation "pg_catalog(dot)br_FR(at)euro" for encoding "UTF8" does not exist

despite

gnumed_v22=> select *, pg_encoding_to_char(collencoding) from pg_collation where collname = 'br_FR(at)euro';
-[ RECORD 1 ]-------+-----------
oid | 12413
collname | br_FR(at)euro
collnamespace | 11
collowner | 10
collprovider | c
collisdeterministic | t
collencoding | 16
collcollate | br_FR(at)euro
collctype | br_FR(at)euro
colliculocale |
collversion | 2.35
pg_encoding_to_char | LATIN9

However, note the UTF8 vs LATIN9.

The manual sayeth:

Some (less frequently used) encodings are not supported
by ICU. When the database encoding is one of these, ICU
collation entries in pg_collation are ignored. Attempting
to use one will draw an error along the lines of
“collation "de-x-icu" for encoding "WIN874" does not
exist”.

which sounds somewhat related.

The database encoding is UTF8. That br_FR(at)euro(dot)LATIN9 had
_not_ been added manually. It is also not actively used in my
database(s).

What is the canonical advice on the way forward here ? Is
the _suggested_ solution to delete the collation or am I
missing to see the "proper" approach to fixing it ?

Thanks,
Karsten
--
GPG 40BE 5B0E C98E 1713 AFA6 5BC0 3BEA AC80 7D4F C89B