cannot drop intarray extension

hi.

---- setup
drop table if exist test__int cascade;
create extension intarray;

CREATE TABLE test__int( a int[] );
CREATE INDEX text_idx on test__int using gist (a gist__intbig_ops(siglen = 1));
drop extension intarray cascade;
NOTICE:  drop cascades to index text_idx
2024-06-03 11:53:32.629 CST [41165] ERROR:  cache lookup failed for
function 17758
2024-06-03 11:53:32.629 CST [41165] STATEMENT:  drop extension intarray cascade;
ERROR:  cache lookup failed for function 17758

------------------------------------------------
backtrace info:
index_getprocinfo
#0  index_opclass_options (indrel=0x7faeca727b58, attnum=1,
attoptions=94372901674408, validate=false)
    at ../../Desktop/pg_src/src4/postgres/src/backend/access/index/indexam.c:1034
#1  0x000055d4e63a79cb in RelationGetIndexAttOptions
(relation=0x7faeca727b58, copy=false)
    at ../../Desktop/pg_src/src4/postgres/src/backend/utils/cache/relcache.c:5872
#2  0x000055d4e639d72d in RelationInitIndexAccessInfo (relation=0x7faeca727b58)
    at ../../Desktop/pg_src/src4/postgres/src/backend/utils/cache/relcache.c:1569
#3  0x000055d4e639c5ac in RelationBuildDesc (targetRelId=24582, insertIt=true)
    at ../../Desktop/pg_src/src4/postgres/src/backend/utils/cache/relcache.c:1207
#4  0x000055d4e639e9ce in RelationIdGetRelation (relationId=24582)
    at ../../Desktop/pg_src/src4/postgres/src/backend/utils/cache/relcache.c:2115
#5  0x000055d4e5a412fd in relation_open (relationId=24582, lockmode=8)
    at ../../Desktop/pg_src/src4/postgres/src/backend/access/common/relation.c:58
#6  0x000055d4e5ae6a06 in index_open (relationId=24582, lockmode=8)
    at ../../Desktop/pg_src/src4/postgres/src/backend/access/index/indexam.c:137
#7  0x000055d4e5be61b8 in index_drop (indexId=24582, concurrent=false,
concurrent_lock_mode=false)
    at ../../Desktop/pg_src/src4/postgres/src/backend/catalog/index.c:2156
------------------------
i guess it's because we first dropped the function g_intbig_options
then later we need it.