The field PAGE_MAX_TRX_ID only matters in secondary index leaf pages. It was expected to be 0 on all other pages until the field is put into some other use.
MDEV-6076 repurposed the field in clustered index root pages for a persistent AUTO_INCREMENT value. MDEV-11369 and MDEV-11424 may repurpose it in further clustered index pages.)
When running innodb.innodb-wl5522-debug or innodb_zip.wl5522_debug_zip with innodb_page_size=4k, an assertion in btr_page_reorganize_low() is failing:
An easy fix would be to relax the assertion:
But I would like to study why this happens. Maybe we are not clearing PAGE_MAX_TRX_ID when splitting a secondary index leaf page.