BUG #17035: assert after commit

The following bug has been logged on the website:

Bug reference:      17035
Logged by:          RekGRpth
Email address:      rekgrpth@gmail.com
PostgreSQL version: 13.3
Operating system:   docker alpine
Description:

after this commit

https://github.com/postgres/postgres/commit/d18ee6f92d9a22b4fae57f515797b2196bf385c7

I got assert

TRAP: FailedAssertion("portal != NULL", File: "pquery.c", Line: 1758)

in my plugin

https://github.com/RekGRpth/pg_task