Had a strange case... the scenario goes like this:

if not seek(...)
    insert into ... (short field list, just keys) values (...)
    tableupdate()
endif
...
replace {four more fields}
tableupdate()

This was a fast job so I didn't really check the result of each tableupdate(); this is on cursoradapters, BTW. The weird thing is that in cases where the record was freshly inserted, the second tableupdate() didn't work. The quick and dirty solution was to run this twice, which worked so I didn't lose too much time on it (it had about 70000 records to create/update), but I'm just curious as to why would this happen at all.

Did anyone have a horse of this color?