SHOW TABLE STATUS reports unappropriate value Max_data_length

When playing around with PBXT MEMORY tables I found that Max_data_length is reported inappropriately for the SHOW TABLE STATUS command:

+-------------+--------+---------+----------------+-------------+-----------------+
| Name | Engine | Rows | Avg_row_length | Data_length | Max_data_length |
+-------------+--------+---------+----------------+-------------+-----------------+
| pbxt | PBXT | 0 | 88 | 1024 | 16777215 |
| pbxt_memory | PBXT | 1048576 | 88 | 184550400 | 16777215 |
| test | MyISAM | 1048576 | 20 | 20971520 | 281474976710655 |
+-------------+--------+---------+----------------+-------------+-----------------+

I assume this is related to the max_heap_table size which is by default 16M.

Same problem for/with PBXT DISK tables.