In the functions rtr_page_copy_rec_list_end_no_locks() and rtr_page_copy_rec_list_start_no_locks(), no redo log is being written for clearing a bit in the R-tree page:
This call is also passing page_zip=NULL, which ought to cause UNIV_ZIP_DEBUG assertion failures when using ROW_FORMAT=COMPRESSED. But, that parameter was changed in MySQL 5.7.5 exactly to address the failure of a UNIV_ZIP_DEBUG check. There code change is associated with a test case change, so we have some hope that the failure is repeatable.
The purpose of this call is unclear. It was added as part of introducing InnoDB R-tree index support.
The bug was found as part of implementing a purely physical redo log record format in MDEV-12353.